I had a roof top tent. The big old ARB one...it came with my Disco when I bought it from the previous owner. I didn't like driving with it, you could definately tell it was up there, especially on on/off ramps.
As far as use, it was a very nice tent and pretty cool in concept. I liked that it was off the ground so no fear of getting wet from the ground if tent placement is mis-calculated. What I didn't like:
- climbing down slippery ladder in the middle of the night to go to the bathroom
- when I camped and used the car during the day, settting up and tearing down camp each day was lousy. You also couldn't keep stuff in the tent like a little home base during the day while out doing stuff in the vehicle. Everything had to be in the car, or in ANOTHER tent to keep stuff in. What's the point of that?
- Packing it up wet, then having to unpack it and have my car sit out in nice weather with the tent setup to dry out after then trip. Somebody who just has one car would really be impacted by this.
I traded mine to a mechanic for a host of repairs I needed on my RZR and my Rover. He said he always wanted one. However, to this day, I don't think he ever used it.