Hi,
I spent months researching different models from around the world and ended-up buying a FloatLift from Sunstream in the US (
www.FloatLift.com). They are more expensive than other models but they're the best I've seen.
You drive your boat between the floats onto rubber skids; press a button on your keychain and the hydraulic rams pull the floats downwards and inwards to lift you and your boat in c30 seconds! Brilliant! The floats are foam-filled so are unsinkable and your boat stays perfectly level throughout the lift or launch!
I have had it since 2003 and haven't had a single issue with it.
Let me know if you want more information or advice on it.
Regards,
Darragh