I actually began doing a serious search on this product yesterday. Seems amazing. Had a long conversation with Chuck at OK4WD in NJ, he was incredibly informative. I've been wanting a roof top tent for a while that would be easy to set up and take down. Initially, I liked the Autohome, but then moved toward the James Baroud due to repeated complaints about pinching fabric on the Autohome. The Baroud also has a few nifty features that I preferred, integrated fan for example. But then I discovered the Alu-Cab and having done some research and my long chat with Chuck yesterday, I'm pretty sure that I'll be picking one up in the near future (i.e. when I convince my wife it's worth $5500 -- obviously I need to get the shadow awning as well, but more about that later).
The Alu-Cab is basically bomb-proof, about 4" lower in height when closed, but just as tall inside compared to other clam shell RTT's, and has a useable rack system on top that none of the others have. The Barouds offer the option of a bit of storage on some models, but for only up to 55lbs, whereas the Alu-Cab can handle up to 225lbs. All three, Autohome, Baroud, and Alu-Cab cost roughly the same for just the tent ~$4000. And now, Autohome also has a few that open with struts, so that is no longer a unique feature of just the Barouds. So all three open with basically the same technology.
Based on scores of reviews, critiques, and conversations, I am of the opinion that they all have their benefits. However, given my preference for the most durable, use of a rack on the RTT, and a slightly lower profile when closed -- the Alu-Cab seems like the ideal choice. And although it might seem contradictory that I would want a lower profile while also use of the rack on top -- I want the option of trying to to squeeze into parking structures with the RTT mounted, but nothing on the rack above, as such my search for the lowest profile.
The Shadow Awning is also just plain awesome. I have the ARB awning and it's fine I suppose, but really quite a pain to put up by myself. The Shadow Awning is super simple to fan out and strong enough to allow for pull ups off the supports (see the videos on youtube). It also connects directly to the Alu-Cab tent, not the rack -- this is possible because of the aluminum shell of the tent.
I will update again when I have this system in my possession. Still researching compatibility with my Gobi Stealth rack. Any other feedback from others who have of these RTT's or the awning in helping me guide my decision would be most appreciated.