I have to admit, I have become an eyepiece junkie. With 3 major dobs now I wanted a couple of sets of eyepieces. My favorite eyepieces are the Pentax XW line. They are not perfect as in the 14mm and 20mm with curvature, but the Type I or Type II Paracorr clears up that curvature. I love the contrast the XW's give and the eye relief since I wear my eye glasses while observing, while most of the time I do. So my main eyepieces are the 20mm, 14mm, 10mm (my favorite), 7mm, 5mm and 3.5mm (the last two for when conditions allow which are only a couple of times a year for the 3.5 and a few more for the 5mm). Anyway, observe with me and you'll find the Pentax XW's in my focuser the most.
I also own the following eyepieces. From Explore Scientific I own the 20mm and 24mm 68 degrees; I had the 24mm 82 degree EP that I gave to my friend Alan so he could have a wide field eyepiece. I also have the 10mm and 6mm Baader Classic Orthos which I enjoy for detail loo the 27mm and 35mm Panoptic, both favorites and now I have the 17.3mm, 12mm, 10mm and 8mm Delos to back up my Pentax XW line and to do some hard comparisons as viewing allows over the next couple of months so expect those.
I have never really gotten into the 100 degree eyepieces though I have tried and sold a few in the past. Recently I have purchased the 9mm Explore Scientific 100 degrees and in my AR102, M42 was wonderful and the 4 stars of the Trap showed great. More on that another time. I also borrowed a 20mm ES 100 degree and ordered one. Then I had a chance to compare it to the 22mm Nagler by TeleVue. In reviewing that I found that the 20mm ES was pretty sharp across the field though the sharpest was near the 75 degrees from center. Contrast was also excellent. Then I put in the 22mm Nagler and WOW! Contrast was superior for me (key here this is MY observation and others will and should differ on their opinions from me as my eyes and preferences are not yours so take my review as my review, not yours. You have to do your own review to find out how they work for you), and stars were crisp and sharp across the whole field, just a tad better than the ES 20mm. The crispness and contrast was enough that for me, I cancelled by ES 20mm 100 degree order for $225 and got the 22mm Nagler for an additional $200. Regrets on the additional cost? Not at all. If you don't have the money to buy then one would be happier with the 20mm ES 100. I did keep the 9mm ES 100 as I want to use it in one of my dobs at a dark site.
I made a point here and I think it is critical. What is right for me, my eyes and my brain is not necessarily right for you and your pocketbook. If you can afford the ES 20mm 100 degrees eyepiece you are going to be very happy with it. For what I am trying to accomplish the 22mm Nagler is a better overall eyepiece based on what I saw, the price, and how I will be using it with my scopes. That is my second point, don't be afraid to go against the crowd and find out for yourself at a star party how different eyepieces your interested in will work. What about the Televue 21mm Ethos for me? Far too much money for an eyepiece I will not use enough so I don't own one. It has tremendous views but I observe 98% of the time deep sky objects and I use wide field on objects that need a wide field or as a finder eyepiece. There are not a lot of those objects and I find that the ES 30mm 82 degree eyepiece is sufficient for that or the 35mm Panoptic. I don't need to spend the money on the Ethos as I have two eyepieces that serve my purposes better for me. For that matter that is why I did not get the 31mm Nagler as I just don't use it enough and the cost is far more than I want to pay for an eyepiece I don't use and its competitor is equal to it or about 90% of it depending on who you talk to.
Third, take your time. If you have to wait one or two years to make a decision do that. If that is too long then six months is no biggie. Wait until you can use the eyepiece and make a decision based on your scope and where you observe and what you have and your observing goals and then make a decision. We rush far too often here in the U.S. as our society pushes that a lot. Sometimes waiting is the best decision to make when purchasing equipment. The objects in the night sky are not going away in my life or yours. Our lifespan is not even a twinkle in the eye of the universe. Take your time. I waited 3 years for a Panoptic 35mm and I got one that has meaning to me as I got it from a friend who left the hobby. Every time I use it I think of Tom.
So there you go. For me the 22mm Nagler is my 2 inch eyepiece in the low 20mm range that is right for me. If your looking for one, try them out and see what is right for you. That is the best advice I can give you and be patient in your purchase and in making your decision. Also remember for many, eyepiece collections outlast a lot of scopes as scopes are upgraded to larger sizes or down graded to smaller sizes depending on our life factors. Last, the very last thing is get out with whatever you have, as often as you can, and just be giddy as you explore the night sky however you do so.