I've always been a ground tent person, and have also tried swags (find them a bit small tbh) and am now seriously considering a roof top tent. Just cant decide on whether to go soft or hard shell.
Here's my 2 cents on your dilemma.
If you expect to fit 1 or 2 people max - Hard shell
If you need to fit 3 or more - Soft shell
If you value speed and ease of setup - hard shell
If you want/need a connected annex - soft shell (could be partially addressed with an awning and side walls but won't be connected like an annex)
If you plan to keep the tent attached indefinitely and clearance into a garage is a concern - hard shell (lower profile)
If you want to store sleeping bag, pillow, awning extension poles inside tent - Hard shell
Durability - I don't know..I read an example where the fiberglass has cracked but Manu. claims it's just cosmetic. Personally, I've had my RTT (hard shell) mounted permanently for 2 years with no issues but I did slide into a tree branch on a muddy off camber trail and gouged my hard shell, taking a chunk of clear coat off. I used epoxy to repair and it seemed to work well. If it was soft shell one of two things would have happened. Little or no damage or it would have punctured the tent. I can never know for sure.
I like RTT and when I'm by myself it's perfect but when I bring a kid, my preference is for a ground tent (safety, bio breaks in middle of night, etc)