Having spent time fixing delaminated side walls I would take Bruce's advice look for one with a hung wall, they can leak but not delaminate. $25k or less would probably be about 15 years or older so maintenance is important. If gas I would choose a straight axle front end over an IFS P-30 chassis a lot less maintenance. After 2006 both Chevy and Ford had good chassis and eng HP. Before that I would look for the WH chassis with the Alison transmission. Also look at things like FW capacity, storage, and CCC. These things are more important to me that the type of roof it has especially storage and the CCC if you plan to fulltime for a couple of years. If you plan to camp in NP's, NFS, SP's CG's without full hook ups them FW, black and grey tank capacities are important also. What sort of mods are you anticipating to make?