I ended up installing the Seymour screen in a client's house about a month ago with some Martin Logan in-wall speakers.
The speakers were very impressive for sure.
The screen was well made. IMO, the screen build quality of Carada is a bit better than what I saw, but Carada doesn't have a AT screen, and Seymour certainly does have a high quality screen. The little O-rings they use to secure the screen are not as tight as I expected them to be. This made installation far easier, but leads me to worry about long term screen tensioning. But, once installed, the screen was certainly properly tensioned and showed no signs of being under/over tensioned, which is great.
I will definitely use Seymour again in the future, and I have no qualms whatsoever in recommending them as the place to go for AT screens.