roof air or basement

Howdy, been busy searching for good used ("our first class A") motorhomes, and finding a lot of good floor plans, mostly with slides.
Some Ford, some Chevy, and some diesel, and all in good shape with good prices. So I stop rambling on, here is my question.
Roof top ac, or basement h/a, pro and cons, noise levels.
Common sense tells me no units on top, lower roof clearance, less chance of roof leaks, but would like to know what others have experienced.
Thanks in advance