Your floor plan is the most important.
Don't get stuck on slides if you are not full timing and only using it for a few days at a time. Slides cut down on the weight carrying capacity and they can be problematic. If you are using it just for camping then the shorter the better for access to campsites. Shorter units can also be parked and used more like cars for shopping and day trips eliminating towing a vehicle.
For us, we had a B that did not have a full time bed. For our current unit we did not want anything over 27 feet as that was the max length allowed at some campsites we like. We wanted a full width queen with no slides but not one that was sandwiched in a corner or that we had to have a slide out to get around. Found that in a 26Q floorplan which has no slides, a lot of storage and cargo carrying capacity, and is built on the wider Ford E450 chassis that handles well and has good towing capacity if needed.
Everyones wants are different but if you are camping think really carefully about the floor plan and overall length and and how much you really need. Try to stay away from longer units with a lot of rear overhang.