I have a modular I lived in for about 4yrs, then rented out for 5yrs and now family stays there when they visit. Never had to really do any work on it. The Condenser had some common thing go out that took the repair guy all of 10min to fix. And, I think rats have jacked up some of the duct work underneath... nothing difficult to fix. It's still sitting on cinder block "pillars" (rather than put a block foundation around it... I'm lazy and cheap).
I'm plenty pleased with it (2 halves, 3 bed 2 bath), especially considering the price. I would imagine the resale value is ridiculously low... but I bought it outright. Don't really care, got my moneys worth and then some.