I would imagine your choices are going to be limited based on the lake you are on.

My parents have always had one that has hard tanks that fill and empty air in order to lift the boat out of the water. Has bunks like a trailer would. Father-in-law has a pulley system style one that lifts the boat from above by use of pulleys.

I like the hard tanks more. But that lake doesn't drain to empty in the winters. Would not be ideal for a lake that drains.