I've got a 06 Bounder Diesel. I lived in it while working in Yuma AZ for about 5 years. Been across country 8 times. I have had no problems with it (knock on wood). I have a CAT diesel and it is pre-DEF. I have fuel and oil filters changed every year along with the oil. In short no problems (mind you oil change is about $300). I change tires every 5 years - RV tires rarely need changing because of mileage but because of sitting.
Any RV will have stuff break - that's what they do!
I say if you have a good price and the rig's floor plan is what you want - go for it.