I have both glass and solid poly sheets in my greenhouse currently. I've also had, in the past, plastic sheeting over part of it. It's a painted steel structure. In my experience I would choose glass every time. Solid poly sheets only as a stop-gap. Plastic sheeting only in an emergency, even though my greenhouse is sheltered from strong winds.
I know it seems easier to stretch a single sheet of plastic over the lot, but all you need is a little tear and some wind rrrrrriiiip! it gets messy real quick. Glass is a pain sometimes granted, but it's the best at the moment IMHO
Funny enough, I've just been reading a page linked to by Aunt Sally
about an idea for a poly-tunnel greenhouse. Mostly plastic construction, no sharp edges etc. but the plastic sheeting remains the weak link! It's Here
it might be of some help to you - Good luck with it anyway