whats a stepV hull

[chumbucket]

The Steplift is just that. It refers to the reverse chines on the running hull bottom. When the boat is brought up on plane, the revers chines aid in lifting the hull up out of the water.
The only comparisons to be made between fresh and salt water are the differences in the water characteristics themselves such as waves and currents. That said, the V20 should be fantastic in fresh water. I've never had the opportunity to try one out in fresh water as there aren't really many lakes locally that can handle a boat of that size. I have a 15-20 minute drive to the salt.
I don't think there is a perfectly designed hull made IMO. They all have shortcomings or tradeoffs in one aspect or another.
I do feel that the V20 is among the best for size/price range. But, this is just my opinion.