I run an Alumaweld Stryker 17, which runs real close to 18 feet. My rig is a tiller, and I run a 50 Yamaha four-stroke. I don't fish rivers with it, but it does just about everything else I want.
I've fished outside at Neah Bay in some vicious rips, and I've run to Possession from Port Townsend several times. There are a lot things I like about the boat, and there are a few things I would change-- like the front deck is too short to fish off the way I like. However, I'm probably going to build a smaller boat for lakes and bass fishing, so the deck issue becomes moot.
Another thing I'm not really fond of is the relatively shallow vee in the hull, which I believe is 10 degree deadrise at the transom. This results in really great mileage, but it also makes for a rougher ride. Also, the way I have my boat rigged, it tends to porpoise unless I keep the motor trimmed down. I can fix the latter, but not the former.
I bought Alumaweld's downrigger brackets, and they don't work well for me. I would have others made next time. The position is wrong for ease of use.
I really love the stability of the boat, and the 50 works quite well. I can fish a long time on a little gas-- a typical day will see me burn maybe four gallons running both the 50 and the kicker 6.
If I were to do the purchase over, I would probably think really hard about the same boat (it's got a different model name now) but in 19 feet with the 14 degree bottom. And I might get a center console with a bit larger engine-- like a 90 hp four-stroke.