I have one for my Pontiac Vibe. Concluded it isn't worth it if you are traveling with just one car because you have to disconnect and reconnect the sleeve. There is some precision parking you have to do to get it done once the tent is up.
However the connection spot on the tent does have a nice huge extra screen door on the tent.
Traveling with more than one car or going someplace like Fort where the car mostly won't move is a different story. You can either sleep in the car (potentially hot) or the option we picked was to use the car for a lockable storage spot. The seal isn't as good as it could be when it comes to bugs but I can fix that. What I will probably do is come up with a magnetic sealing screen for my sunroof then try sleeping in the car.
This was a Sportz tent by Napier. Sturdy material and a tall roof so its not so great with an unobstructed wind but good for being able to stand up...definitely helped to have the hatch up stabilizing the tent.
My tent is just 8X8X6...small tent for a small car. Minivans and fullsize SUVs connect to bigger tents in the Sportz line...I wish they would arrange to optionally connect the sleeve to a screen house.