Welcome to the forum Pling, I have a Tambo Cooper and have not had any problem with it, the canvas is great and the trailer is strong. The team at Tambo are great and I have had no problems with the trailer, I had to get a wall repaired which was out of warranty and it was done for free.
Cannot comment on AT, they have a good reputation at well. Check out my thread with links below, where are you located?
GG