I recently picked up the 20mm and 9mm Lunt XWA 100º eyepieces. Now I've never looked through a 100º eyepiece and have never really been tempted to but the recent reviews of these coupled with a very tempting price sucked me in.
I've had maybe four nights with these and while conditions weren't the best, I want to share my thoughts on not only these specific models but the 100º FOV itself.
My main eyepieces for the last several months have been Delos. These are used in my C8. 72º is plenty wide and all the other aspects of the Delos are superb so there's really no reason to want for more. In my scope (and I use the f/6/3 reducer/corrector) the Delos provide just about pin point sharpness from edge to edge, not withstanding an issue that I've posed about with regards to some anomaly with my eye.
The first thing I found with the XWA's is that it's not easy to see the field edge. I can but it requires some serious looking. When I do, I find that they are almost as sharp at the edge as the Delos, and I mean so very close. But, and this was the big "Ah ha" for me, it doesn't matter! I mean they could be poor at say 80% of the way from the center to the edge and it wouldn't matter. With a field this big, there's no way I'm going to be directly observing anything at that distance out from center. So all that field serves the purpose of being essentially peripheral vision. Al Nagler has used the term spacewalk to describe his Naglers but I never got that with them. The field edge was just too visible. You always knew you were looking through a tube; a wide one but a tube nonetheless. With 100º I get it. It's very much like being out in space.
Now a bit about these particular eyepieces. They're no where near as heavy as I expected. In fact the 9mm is quite light. The eye relief is very comfortable (not for glasses of course). I can comfortably view through them and be able to blink with out my long eyelashes swiping across the eye lens. I seem to be able to snap into focus quite easily with both of them. Not sure to what this can be attributed to but it's definetly noticeable.
What I will be doing next (and possibly tonight) is comparing them with my Delos in other areas such as contrast and throughput. The Delos really seem to reveal star colors and I'm anxious to see how the XWA's do in this regard.
Finally, I'm sure that the Ethos are superior but at the price difference (better than 2x) I'm not sure the differences are enough for me to justify the cost. But.... you never know. :-)