I have a pontoon kayak made by outcast I like quite a bit on lakes and moderate rivers. Tracks really well but not as good as a real kayak does. It weighs around 20 pounds and it not all that bad to carry but I would not want to drag it over rocks and such.
Have used it some in the sound out here but think the base is a little too wide to deal with current and wind. Basically with a heavy current I have to come and go with the tides. They really built it with fishing from it in mind which comes at the cost of the water slicing properties of a true sea kayak.