Good comments so far
before 2007 means you smell the exhaust which I do not like and requires a side radiator as the slobber tube will make a rear radiator problematic. Nothing wrong, except cleaning a rear radiator with a slobber tube can be a PIA
2007 - 2010 is the sweet spot imo. Diesel exhaust smell goes away and so does the slobber tube so either a side radiator or rear radiator are feasible
2010+ this adds DEF which I do not like, but it would not stop me from buying the MH either. I really like some of the new stuff they have added to MHs