How long is a piece of string??? Very tough answer!!! Maybe 6 of one and half a dozen of the other???
Tubes that never touch the water are a waste of time - hard noses are I suppose to stop the tubes being ripped off.
Probably the best boats ever built to take rough water are the ones built by ocean dynamics - I just love the "no transom design"!!!
Personally I think a lot more thought should go into making boats better balanced - lower c of g - better fore and aft balance to avoid "pitch poling" etc.
But as to the actual inflatable nature of the tubes themselves - yes they do absorb shock but then the hull takes most of that before the tubes hit!!!