Prescription sunglasses = BAD - Polarizing effect makes it difficult to see.
Regular glasses work fine, and the diopter adjustment helps immensely. Bigger trouble is light leak from the sides of your glasses getting in the way.
I have tried using the diopter and no glasses so I can put the eye-piece tight to my eye in bright sunlight. But my astigmatism is still there, so even though I can get it focused, it is still distorted.
I think i'll stick with the LCD for the time being. I have found it amazingly useful and since Summer is ending I think I can put of getting the EVF for a while yet. Besides I have my eye on a Super Tak 105/2.8 that will be a much better expenditure for me.
I have the EVF and it's usable with glasses but not very comfortable. I do find I use my left eye more if wearing glasses as the nose-touching is no issue and I'm left-eyed. My degree is very low so I just take my glasses off without any diopter adjustment when I need
I went ahead an picked up one that a fellow on rangefinder forums had available (via a tip form a generous fellow board member here). He gave me a great price because Amazon has them on sale new for $90 off at $260 so I picked the lightly used one up for $200 shipped. It arrives in a few days.
Good buy! I hope it works better for you than the fixed EVF on the 7, which i quite dislike, too small, uncomfortable,and wierd smearing. I read that it was the same as that on the A57, but I never found that one to be a problem at all.
NEX-6 with eyecup is okay. Same issues with polarized sunglasses of course. I wish the EVF opening was rubber coated like on the old Nikon FE/FM style cameras, but it isn't, AND it is textured (bad) like the rest of the body. I'd love a snap-on rubber rectangle that wasn't as deep as the eyecup, but it is acceptable. More, I think the "clicks" on the diopter are too fine and easily nudged. I prefer hard notches over this more delicate adjustment. Probably allows better fine-tuning I guess.