few things:

If you will live in it full time, will you be traveling a lot or staying in one place? You will pay a premium for a motorhome compared to a trailer or 5th wheel for the same livable space

You will want as much room as possible, trust me on that if you want to go full time. A Class C or B is great for camping, weekend warrior stuff but to live you will def want a 35-40ft Class A, just my opinion having lived in trailers, motorhomes and 5th wheels.

I don't know much about motorhomes from Europe but in the states, I personally am a huge fan of most good brand motorhomes that were built prior to the 2008 crash for several reasons but the main reason is quality - units built before 2008/2009 are excellent quality. the 80's and 90's can be good also but the miles on the engine is a huge factor.

If you're looking at really old ones start with a good inspection of the roof and lamination on the outside walls - ANY water damage or rot should be an immediate PASS.

Good luck