Quotes from review of 21mm Ethos on Alpha Lyrae website.

First Light
[T]he eyepiece and the telescope just melted away and started delivering some of the best observing I have ever experienced. With the Ethos you are able to actually look around the view, much as one does with the unaided eye and the experience is truly spectacular. … The superlatives (and even more colourful language!) being uttered by observer after observer about that view of the Double Cluster confirmed that this is a very special eyepiece indeed. … When tiredness finally set in and I decided to call it a night, I realised I was still using the 21mm Ethos and had not changed the eyepiece once during the entire 7 hour observing session.

M42
Viewing almost 45 arcminutes of sky at over 130x is extraordinary, the twists and tendrils of glowing nebulosity that cradle the Trapezium seemed to standout as never before, benefitting from the darkening of the sky background and improved contrast and visible detail. And the same experience was repeated with other larger DSOs such as M31.

Moon
While under the stern test of a bright moon I checked for any evidence of internal reflections but saw none, indicating an excellent level of internal baffling.

Conclusion
The 21mm Ethos is stunning eyepiece. The experience of true immersion in the view has to be experienced to be believed, and it delivers this with a flat field, sharpness to the edge, no astigmatism and no internal reflections. The advantage of the extra field for those of us who like to use un-driven Alt-Az mounts is fantastic and in long focal length telescopes like my 11" SCT, you are no longer restricted to lower powers to achieve those wider fields of view.

Excerpt from Astronomy Now review of 21mm Ethos in 12" f/10 SCT

Over the next few days a waxing first quarter Moon made its appearance in the evening sky and I began observation with the 21mm (145×). The 41 arcminute field enfolded the Moon with alacrity, encircling it with a generous dark surround. What made these observations unusual was that in order to view different features at this moderate power I had no need to gently slew the telescope towards them; I merely viewed at will, my eye alone alighting on what it wished. Like an Olympian god, incredible detail was revealed wherever I gazed.

Quotes from Cloudy Nights Reader's Choice Award 2010:

Once again, Tele Vue was the leader in the field, with the most products voted into the top.

3.7mm Ethos-SX

Not content to rest on their laurels, Tele Vue once again widened the field with the introduction of it's 3.7mm Ethos SX. It's 110 degree field matches the AFOV of the LEM simulator that Tele Vue founder Al Nagler worked on for NASA in years past. I was fortunate enough to review one of these for the BBC recently and the eyepiece is (like the rest of the line) absolutely fantastic, and it's planetary performance easily rivals (if not bests) traditional purest "planetary" eyepieces.

21mm Ethos

Making a return this year was the 21mm Ethos. Yes, it reallly was introduced in 2009, but so late in December, most of you didn't get a chance to see one until the 2010 observing season. I suspect that played into your nomination and inclusion of this powerhouse again for 2010. While there are imitators, you've made it abundantly clear there are no substitutes.

Astronomy Technology Today excerpt from 3.7mm Ethos-SX review

• There were nights when I didn't even bother to bring out my eyepiece case; the Ethos-SX was all I needed.
• What's incredible about using a well-corrected, high-power eyepiece like this for planetary viewing is that you can let the object drift from one side of the massive FOV all the way to the other side without any loss of resolution.
• There was no scatter or ghosting no matter what objects I observed.
• With smaller and faster scopes, the magnification is perfect for detailing globular clusters, but within the wide swaths of sky that we normally associate with medium power!

From Astronomy magazine's 2010 Star Products -- a yearly list of outstanding products.

Tele Vue 21mm Ethos eyepiece

The first view you have through a Tele Vue Ethos, regardless of the focal length, will be one of those astronomical moments of a lifetime. Capitalizing on the company's success with earlier focal lengths, Tele Vue introduced a 10mm Ethos, as well as the 21mm model we single out here. Like the others, the 21mm Ethos offers an incredible 100-degree apparent field of view. One look and you're hooked for life. For the true connoisseur of fine eyepieces, the 21mm Ethos offers panoramic views of large-scale objects in unprecedented crispness and clarity.

Excerpts from Sky at Night Review of 21mm Ethos

• "...may just be the new crown jewel for ultra wide eyepiece lovers."
• "Visually, the performance is stunning. The field is flat and the whole view comes to focus at the same point. The eyepiece also lacks any detectable astigmatism - stars focus to points, not crosses."
• "...interior light baffling is excellent, so there are no problems with internal reflections or stray light."
• "The 21mm Ethos is an amazing eyepiece: the finest (and only) 'über wide' in this focal length on the market. Its focal length is a great addition to a superb line-up..."
• "The Ethos's field size is astounding. With the introduction of the Nagler design, it's said that Tele Vue defined the term 'spacewalk'. If that's the case, then these eyepieces redefine it. A 100º apparent field of view is, at the moment, the next best thing to being there."
• "The optics are crystal clear. The 21mm's kilo of glass is about as close to completely transparent as one can imagine. The views are superb for any application, from deep space to lunar and planetary observing.".

Sky & Telescope Hot New Product for 2010 Award

Ethos 10- & 21-mm Eyepieces
Observers world-wide have raved about the experience -- two new Ethos eyepieces (10- and 21-mm ) from Tele Vue, the company that pioneered the 100° astronomical eyepiece.

Excerpts from SkyNews Review of 21mm Ethos

• In my 12.5-inch f/4.8 PortaBall reflector, the 21mm Ethos provides a magnification of 72x and a stunning 1.4-degree field of view. I enjoyed the best view of M31 that I've ever seen though this telescope, with tight stars at the edge of the field.
• When the 21mm Ethos was used in a Tele Vue 76 refractor, the resulting magnification of 25x and the humongous four-degree field of view provided an outstanding view of the Pleiades star cluster floating in a star-rich field.
• While the 21mm Ethos excelled in the short-focal-length refractor, it was most impressive when used with the SCT -- so much so that I'm going to christen this focal length the "SCT-Ethos." SCT owners are no longer restricted to relatively low magnification to enjoy a comfortable field of view.

Excerpt from Astronomy Technology Today Review of 21mm Ethos

When I compared it with my other 2-inch wide-field eyepieces, it became obvious that the Ethos provided a completely different experience. I'd liken it to looking through binoculars with one eye closed, then popping the Ethos in and "opening the other eye". The difference was indeed that dramatic.

Excerpt from Astronomy Technology Today Review of Ethos Line

It didn't seem to matter that I was looking at an AFOV that seemed like twice that of my Naglers, all of the Ethos were perfectly, and I do mean perfectly corrected right to the field stop. Stars looked exactly the same in the center of the field as they did right at the edge.

First Editorial Impression of 10mm Ethos from Astronomy Technology Today

We got our first peek through Tele Vue's latest Ethos, the 10-mm, and its performance was truly as incredible as any in that growing family of hyperwide, supremely-corrected, high-fidelity eyepieces. You'll have to try one in person to understand the significance of Tele Vue's accomplishment - words cannot capture the experience.

Sky & Telescope Hot New Product for 2009 Award

Ethos Eyepieces
In recent memory, no new product has received more universal praise than Tele Vue's 13-mm Ethos eyepiece. With its unprecedented 100° apparent field of view, it shows at least half again as much sky as any other eyepiece of the same focal length. Now Tele Vue has introduced the same 100° field in eyepieces with focal lengths of 6, 8, and 17 mm.

8mm Ethos is Cloudy Nights Reader's Choice for 2008

Back in the waning months of 2008 we asked you - our forum members - to nominate and then vote to choose the best and most interesting gear of the year.

Tele Vue 8mm Ethos
Well, you've got to hand it to Tele Vue. And apparently, you did. They were your landslide pick in 2007 with the 13 Ethos, and they've repeated the performance in 2008 with their introduction of the 8mm Ethos. For those who have been living under a rock, or on a deserted island in the south pacific (or both), the Ethos line of eyepieces is the first commercial widefield to break the three digit AFOV barrier. The performance of the 13mm was nothing short of amazing, and the 8mm follows in it's bigger brothers footsteps. Who would have thought that the 82 degree field of yesterdays uberwides would ever feel restrictive?

Excerpt from Stephen James O'Meara review of Ethos 13mm in Astronomy magazine

Moon-lovers get an extra bonus because the Ethos brings out sharp details across the Moon's face. This gives the disk a three dimensional, curved quality. Through the Ethos, it looks like you're orbiting high above the Moon's curved horizon.

Astronomy Technology Today excerpt from 13mm Ethos review

• I think the most memorable view was M57, it truly felt like I was floating in space above the nebula - the telescope had disappeared!
• The immersive view delivered by the Ethos' 100-degree field of view combined with its amazing clarity and pinpoint definition is like putting an IMAX on your telescope.

13mm ETHOS' in bino-viewer! Cloudy Nights Review

• WOW! OMG! (and many "expletives deleted"!).
• Forget about the 100-degree field (well...I know you can't but...), this is quite simply the finest eyepiece I've ever seen - period!
  Contrast, sharpness, light-throughput, etc. are all just amazing. There is simply NO ghosting or other internal reflections...the background is jet-black and the stars (even in my 28" f/3.66)are absolute diamond-points to the very edge!
  I've owned and used all of the "gold standards" over the years and NOTHING I've seen can match this!
  Along with about a half-dozen other observers we did "A/B" testing with other top-of-the-line 13 and 14mm eyepieces (M-51, Thor's Helmet and M-42 were the targets). EVERYONE agreed that the ETHOS seemed to add additional inches of aperture. The increased detail in all of the objects was instantly apparent!
  As a bonus, the fine detail on Saturn equaled or exceeded the best "planetary" eyepieces any of us had ever used. And, again, NO ghosting or internal reflections. This baby does it all.
• And, as for the 100 degree field, Vic said it best... "you feel like you're going to fall in"..."the scope just gets out of the way and it's like you're standing in space looking at the objects".
• If I were only going to have ONE eyepiece (or one 'pair') THIS IS IT!

Sky & Telescope Review Excerpts of Ethos 13mm

• Rated 5-stars: "Sensibly perfect. No meaningful improvements possible."
• Just as the original 13-mm Nagler set a new standard for deep-sky observing in 1981, the Ethos sets a new standard today. Owning one will guarantee long lines at your telescope during any star party.
• [I]f I were dropped on a desert island tomorrow with the 12-inch scope and only one eyepiece, I'd want it to be the Ethos.
• Some of the views were simply stunning. The globular cluster Messier 13 in Hercules appeared as a sprawling sphere with thousands of resolved stars, many sweeping outward in sinuous arcs.
• Even under the most critical examination, bright stars look sharp and round across the entire field.
• The Ethos hasn't sacrificed one bit of on-axis performance in achieving its 100° apparent field.
• [T]he view of a starry sky with the Ethos and TV-NP127is is nothing short of breathtaking.
• Besting the fields of other astronomical eyepieces by more than 20% in diameter and more than 50% in area, Ethos is a stunning optical achievement.