When we moved here 4 years ago I decided to go for polycarbonate instead of glass. The first one delivered from B&Q had a number of cracked panes, so had to be returned. This took 2 weeks for them to collect, and a further 2 weeks to deliver, they wouldn't send the replacement before they had checked out the broken one. Only problem was, the second one was also cracked, so was sent straight back on the same delivery van. We never even got to trying to put them up
I now have a glass one (8x6), and despite the fact we have a VERY windy back garden it is still as solid as a rock and I've never had any problems with it.