If I might make a suggestion, it is possible to have the best of both worlds.
I own a Pelican SIK, and it is set up for fishing, but my favorite 'yak' is my Advanced Elements Convertable Inflatable Kayak. It only weighs 47 pounds, can be carried in the trunk of your car, inflates, and sets up in less than 10 minutes, can be set up easily for either one, or two people, can be used 'open', like a canoe, or with the zip in spray decks, as a SIK for one, or two persons, and I can use either the drop stitch floor for stability (you can even stand on it), which makes it handle like a really light Jon Boat, or the backbone, which makes it out-perform all but the most expensive sea and racing kayaks. I use the backbone most of the time. I don't know what it's rated for, but I regularly go through Class V rapids in it with little trouble (it's just a little long, at 15', for a whitewater boat). I even bow fish from it (carefully, of course). Check this out:
I have had all kinds of kayaks, and canoes, and this is by far the absolute best boat I have ever been in. It even has a sail-rig available for it (but I don't know why...you don't need it. This boat makes 5 knots without even working up a sweat). It performs at least as good as any hard-shell, and better than a lot of them.
Just my 2 cents........