Hi,
I cant comment specifically on the models you've referred to, although I have a jet jwbs-16 which is a smaller cousin of the jwbs-18 and i think it's a fair bandsaw that could be improved if it was heavier in order to minimise vibrations.
If I were you I'd try to see each model in the flesh and check the following: vibrations while running, easy access to upper and lower guides to accommodate different width blades (a real chore on mine) and the existence of a quick release mechanism. Also check rigidity of fence and worktable dimensions.
If you cannot test each machine personally go with the heaviest model. Bear in mind though that most of the performance is related to the blade quality and not the machine itself, but weight and stiffness in construction help a lot