It's still a bit immature as tech goes so there's not a lot of usage yet and there's not a lot of competition either. I think Sony have literally just unveiled a prototype (http://www.engadget.com/2014/09/19/sony-smarteyeglass-prototype/) but it's a long way from sale.
In regards to Google Glass in general, I was really excited about the concept but I'm not sure how much I'd get out of it beyond what normal smart phone usage already provides. There were some good articles on the beeb by their tech-ed on glass that's worth a read: Google Glass - a fascinating failure? and Taking Google Glass for a run.
but if you're just after PoV filming then the GoPro seems to have the market sewn up nicely.
Hope this helps.