I have an old 5m Humber inflatable I use for diving.
Easy to tow, I used a Ford Fusion 1.4 tdci and you wouldn't even know it was on the back.
Easy to launch/retrieve.
Lots of deck space as it has a 40hp tiller steer.
Great for diving the Lochs up here.
Seaworthiness, was out it a brisk sea earlier this year going from Oban to the Sound of Mull across the Firth of Lorne and we got buffeted quite a bit by some biggish waves, we got there and back OK, just took a bit longer and my biceps grew in size trying to keep the boat going straight in a strong breeze.
I'll be upgrading to a RIB next year as I'm looking for something that will take me a bit further offshore.