There are a lot of dynamics involved - it's not as simple as only how long the wheelbase is. One major factor is how much overhang there is past the rear axle - the more overhang, the more the "tail wants to wag the dog." The less overhang the better. Having said that, yes, generally speaking a longer wheelbase is a more stable and predictable ride. The shorter the wheelbase, the more steering input is required which can get very tiring after a few hours.
Be sure and make the trip up Lazydays at Seffner - they will have a huge selection to look over.