I feel a rally coming on ...
Don't have the information you asked about but I went through a similar process. Since vehicle information is easier to obtain, I focused on the coach:
a) the "systems" -- water, electric, heat, air, etc. My conclusion was that these are largely overlapping among the various RV manufacturers, with the same vendors appearing over and over (dometic, fantastic fans, etc.). So, quality is likely to be similar at least out the door. In a used RV, due diligence is about all you have.
b) safety of the coach - hard to get good data. Martha sent me a book which I have since sent on to someone else, but the concern was that slide-outs and fiberglass shells are potentially a risk in a roll-over or side-impact crash. Not sure just what to do with these unsubstantiated frets, but just something to be aware of.
c) watch out for storage costs if you need to do that. I'm sure it varies a lot town to town, but if you are not planning to store it at home it can be expensive.
Betcha Audrey has a web site or two that will help.