I don't know much about the coaches themselves, other than it seems like DynaMax owners are generally really happy, and Thor owners tend to be less happy.
As far as a chassis goes... I think you'll like a true MDT chassis more than a pickup based MDT. I really like the Freightliner M2 with the MB/DD diesel (MB and Detroit Diesel are one in the same now... I'm not even sure they offer both names anymore) . Way better visibility and a nicer ride than a Ford/Ram 550/5500. Infinitely better engine access, although the MB diesel is a little more maintenance than the Cummins option.
I personally would won't buy any diesel with the Bosch CP4 fuel pump, which includes the Ford diesel. $13,000 fuel pump replacements after warranty are not something I ever want the possibility of.