I agree with others that a MH, due to complexity and the simple number of components, is more likely to have issues. SOME may have a better build grade due to cost, but the cost is more about the powetrain than it is the coach (at least on the more cost-effective units).
The other factor I would think at play, however, would be the ability for the DIY repair. MH's have many more components that the average DIY'er can't repair. Most of the work needed on a TT or a FW I can do myself, meaning it spends minimal time in the shop. Put me in a MH and you've added a host of things I wouldn't be able to touch!