Never tried one but I think I'd expect about the same out of it.
One feature I would appreciate out of something like this is to be able to record every moment of your life that you are wearing it in case you capture something spectacular. But then there is the whole creepy privacy issue that pretty much ruins that. And you'd also have to wear it all the time for that, unless I needed full time prescription glasses it's something I'd never want to do.
In the end I think I'll be sticking with my touch phone for a very long time as my personal computing/media/camera/navigaton/etc. device. I also found tablets too cumbersome for my liking, glass feels similar to me, 5" screen in my pocket feels just right in terms of usefulness vs. encumbrance.
