In the pictures I posted above the use might be different, but the basics of kayaking are the same. A sit in kayak with a skirt is generally going to give you higher performance and control than a SOT kayak. I have swum in that playboat several times and it has never sunk, even when I forget to inflate my float bags.
I'm sure that there is somewhere near you that would be willing to do a demo of different boats for you. After about 9 years in kayaks I am infinitely more comfortable with the control that a sit in boat provides. Don't rule them out for fear of sinking.