We've had our 2012 Thor Four Winds Class C 24C for five years and have really enjoyed it.
The floor plan is nice and I don't even mind the bed in the corner, I've learned how to work with it. We have had the inevitable leak in the cabover section, but that got fixed okay and insurance even paid most of it. The cabinets are all still together as are the drawers. Nothing is falling apart.
The biggest headache is now the A/C. It works great (I call the MH the big fridge), but is leaking inside the coach...DH is still trying to correct that (some drain is plugged somewhere). The ceiling looks okay as does the roof. And there's an area around the rear left light set up that is kind of scary...it's delaminating and that needs to be checked ASAP.
Taking care of this stuff...in fact this camper is vital. It's a second home and a nice tax deduction (just like the S&B house) and too expensive (and fun) to neglect.
ETA: Obviously I'm only addressing an opinion on Thors, which so far has been a good company to deal with. Also the dealer is important. The outfit where we bought our camper has become a ...gulp...Camping World dealership...ugh. But many of the same people in the service and parts dept. are still there. So far so good. Now there are tons of salespersons all over the place and lots of stuff to sell...not nearly the customers though...