I noticed someone said to stay away from razorback steel canopies, I've had one for a couple of years now and it's by far the best I've ever had or seen. Stronger and more secure than the others, better locking system than most. The roof rails that come with the canopy are already rated to carry 100kg and the roof has been tested to withstand 4 times that amount!
They are fully trimmed/lined inside, have double rotary automotive style locks, rear window demister, option of central locking, they are made in the same way vehicle roofs are made. The rear door isn't just a large plastic or glass window but rather is a framed steel door with a large window lol I sound like an advert but I just love mine and think they are certainly worth looking at if your after a quality canopy.
Mine originally did move a little on extremly rough off-road stuff (rock hoping etc) but once I re-did the clamps myself it's been good since, I believe that they now have a improved mounting hardware as well. To the other person that had one move I'd suggest to check the clamps/fittings are done up correctly and if that doesn't work have a chat to Razorback and see if they can do/suggest anything to help solve your problem. They were good to talk to in all my dealings with them