I've had several of each and I will never own another corrugated aluminum RV.
Way too hard to keep from leaking and dents and dings appear out of know where. And it's not a matter of maint. alone.
Some will say aluminum is cheaper to repair but that has not been my experience. A shop that specializes in RV bodywork can do undetectable repairs at a competitive price and ins. rates reflect that.
Besides, I don't buy vehicles based on what it costs to fix bodywork.
None of this is meant to be a slight to those that have alum. RV's. All RV's are built to a price point and those with alum body's fill a niche.