DoubleE - one thing I've always been tempted by are the "drive on" floating type lifts.
The idea being the lift floats always, you then drive on.
Big disadvantage is that to get off the lift you have to use a crank style system to "push" the boat off.
I like that the boat is out of the water, and you could probably put a cover onto this style.
I also like that they are much less likely to sink if one is holed than a bladder.
A risk of any floating type would be if you forget to pull the plug and your tarp collapses full of rain.
No floating lift is sufficient for the big waves we get.