I have Oakley X-metal with Oakley prescription lenses, Oakley M-frames with prescription lenses (inserts cut into the wraparound part) and a pair of ESS glasses with prescription. I've not had much issues with looking over or frame blocking, but I also use a retention strap for anything other than static shooting.

Oakley has a better glass - slightly, and I could deal with extra cost, but I don't like their CS so I am going to stick with ESS from now on, they have been more than adequate.

I also shoot uncorrected fairly regularly - you can't be sure you'll have time to put glasses on or if they won't be knocked out, can you? Funny thing is that short-distance accuracy doesn't suffer at all since with my myopia I can pretty much concentrate only on front sight and nothing else.