I just purchased a used Seayak a few days ago and was finally able to get it on the water yesterday. My boat is quite old, most likely early 90s with the smaller cockpit. I am 6'2" and 180lbs and the boat fits great. It is such a fast, responsive boat with the right strokes. I did some practice with my rolling and it was incredibly easy, given my "rustiness". Couldn't land a hands roll, though... I do not have the rudder installed, and probably will not get one. I would like to work on my paddling skills before I take the dive into the "rudder realm". Given that the boat is at least 20 years old, it has held up incredibly well. I had people asking me yesterday if it was a new boat.
All in all, it is a great boat that has lasted 20 years, and will probably outlast me.