I would look at which build/floorplan rig you like more independent of the chassis. Both have their pros and cons and whichever one you get, if you have problems you will wish you got the other
The bigger thing to make sure you are good with, the 550's "Super C's" can be plagued with low OCCC and boast 10k towing, but in reality there is only about 5k between GVWR and CGVWR. Coming from a Class A diesel pusher, this may be a deal breaker, depending on you needs. Just want you aware before you get too deep on your research.