What you want depends on how you will be using them.
Where will you be using the kayaks?
(Ocean, calm lakes, rivers, streams, ...)
How will you be using them?
(Just paddling around for a hour before sunset, half day trips checking out the wildlife along the shoreline, a day of fishing, multiday trips with 100 lbs of gear, ...)
Do you mind getting wet (sit on top), or do you insist on staying dry (sit inside)?
How important is kayak weight? Light materials cost more and need more care to avoid damage. Heavier materials allow you to beach the kayak just about anywhere, and store it anywhere, without worrying too much about the abuse you give it.
Will other people be using (or borrowing) them?
We got a couple of Wilderness Systems Tarpon 120's several years ago and they work great for the way my wife and I use them. We keep them up at the lake for general use during the summer but use them around the SF Bay area during the winter months.
-Dave
