I have a polycarbonate one, the frame itself is sturdy but the panels are flimsy, I had to silicone them into the frame as the clips supplied with the greenhouse didn't keep the panels in when it got windy,
5 years later i'm replacing the roof ones as they've gone brittle in the sun.
if you can afford glass, get glass. If I could go back I'd get glass even though it would have cost me nearly double.
however on my allotment I have a polytunnel nearly three times the size of my polycarbonate greenhouse for the same price and that thing laughed at the storms last winter and the winter before. But it isn't the prettiest thing in the world.
so it depends on what you want - size or prettiness
If you are replying to the original poster then it's a bit late, those posts were in 2013!