I will add this to the thoughts of aluminum roof's.
You can not walk on them unless you lay 1/2" or thicker down...
TPO, Fiberglass you can..
Aluminum roof's can develop pin holes... Not good.
Most Aluminum campers develop leaks from the running lights and their front window....
I would not get a camper with a front window.... The bad is you can not tell if it or the running lights are leaking. The water ends up running down to the bottom of the bed area then runs over to the corners and down where the jacks are..... We see aluminum campers with bulging sides (even mild) that is caused by the bed area starting to sag from wood rot.
Watch for those bulging sides!
Jim