I know several cat sailors that have owned these. None have complained, so I think that speaks volumes.

They really are only good for one person, maybe a couple. Add a dog, kid, etc. and you'll be looking for more room quickly.

A separate RV is great, but that's another whole drive train to maintain; and no matter what you do with it, you're only getting 7 mpg.

A separate RV does have other advantages, mainly the larger water and waste tanks (the larger, the better, allows more showers, etc.). You also tend to get more storage with an RV.

As for the pickup models, buy used and save tons of money, even if you have to add the power jacks separately. One guy I know used a power drill to speed up the manual jacks (still have to do one at a time, of course).

The pop-up models promise less impact on gas mileage (drag), but then you add the complication (maintenance) of the tent portion. Usually not a big deal, but if you fold it up wet, you'll want to open it when you get home to let it dry out (avoids mold/mildew). If you buy used, you'll need to be sure the canvas doesn't leak.

Be aware of the normal things to watch for when buying any used camper: water damage, leaking roof, functionality of appliances.

Hope this helps.

Mike