There are several manufactures out there and all of them have features that set them apart from each other. Roll-a-home, Aspen, Bunkhouse, Time out, Roadman, and Lees-ure-lite just to name a few.
Some set up faster than others, I think the lees-ure-lite has the fastest set up time. Time out has the largest floor or tent area when set up. Then all of the others have their own little features to compare.
I used to own a time out camper, loved the room, but you must unload everything when it is set up because the trailer bed and top is your floor and bed.
I now own an older 1998 Bunkhouse camper that has a huge bed area, a little larger than queen, a dressing area down below, and a large awning to set under. All of the things loaded in the trailer can stay in the trailer and can be accessed from inside the trailer after set up just by lifting a section of the bed. The trailer is also accessible from outside when the camper is folded up.
I love the access from inside, it makes it much more pleasant to pack up everything when it is raining, without getting wet, until you fold up the camper.
The bed is up on top of the trailer and the dressing room floor is on the ground.
The Aspen trailer is set up with storage the same as the bunkhouse.
You will need to decide what features are more important to you.
I used the spare tire well on my bunkhouse to mount a motorcycle gel cell battery in, then wired up led lights on the inside with a dimmer for light at night. I also have 12 volt outlets to operate a fan all night when hot, and charge cell phone and Bluetooth headsets while sleeping. The battery will last about 3 days and night before I have to charge it. I have a small charger wired in so I can plug in at a site and charge it, or it will charge as I drive to the next campsite.
Here is a pic of it behind the bike, and then set up by the Spyder.