My pontoon is a Creek Company Sport, now a Creek Company classic. It is 8-10 years old and still holding up. I got it used a couple of months ago and it's never let me down. My friend has a Creek Company classic and he takes it down the McKenzie probably every weekend. I'm more of a lake guy myself but have read a report online of someone going on a 3 day float in Alaska and it held up. Check out ebay for them too. You can get one for under $200. You can also get a XR8 and XR9 which are better pontoons highly discounted off ebay (check out the no reserve auctions, not buy it now).
Good luck and you won't regret it. Mine goes everywhere with ease. It weighs 45 lbs so I can toss it on my car, a couple tie downs and I'm off. From car to water in 5 minutes and vice-versa.
FRC