This thread could go on for a while. My own experience after owning several RV Diesel pushers and a gas RV, the moment I drove a Prevost I was
hooked. The ride is smooth and quiet. The Prevost construction is A+. The convertors are all very miticulous and thorough. The componants used
are found in the marine world as well as the RV industry. These Coaches don't even hit their stride until they have over 100,000 miles on them.
Yes, you will have to maintain them & replace parts that go bad, no different then any other machine. Parts are less expensive than Mercedez or Porsche parts, more expensive than some american parts.
The best advice I can give you is to do the research, ask a lot of questions, spend some time on the road seeing and driving Buses, come to a rally and see and meet prevosts and owners.
Maintence records and knowing a history of a coach will go a long way in helping with the decision making. Outside paint colors matter more than interior colors, you can change the interior easier and cheaper than changing the paint outside.