Background: I've kayaked for about a year seriously and have been to 10,000 Islands for a trip in a real sea kayak (Nigel Foster Shadow). I've paddled canoes all my life.
I really enjoy my Sprint. I tried all the 14 foot poly boats at KC Paddler at a demo day and kept coming back to this one. I got the rudder with the kayak. I have used it mainly on small Ozark streams (Maries River, Moreau River) and I wouldn't hesitate to use it on the Missouri River or a big lake. It cuts through waves up to about 2' pretty well in my one test on a lake. Boat wakes don't bother it.
The kayak tracks well and glides well for it's length. It is more "lively" than the Tsunami, Zoar, Manitou, and other boats I tried. It turns easily either by leaning or by edging, but don't expect miracles. I can turn 90 degrees in about a boat length or less with one stroke.
Speed and Stability:
I clocked myself this weekend on GPS and averaged 3.3 mph over 1.5 hours and 5 miles going upstream and then returning. I sprinted for about 20 seconds at 4.5 mph but I wouldn't want to do that regularly. 4 mph seems to be the highest speed that I can sustain without straining. The kayak is not a speed burner compared to longer sea kayaks, but it is a great compromise that is faster than a friend's Necky Looksha Sport and a Dagger Specter. As for stability, I haven't edged it all the way over on it's side since I don't have a skirt for it (I hate skirts in summer), but it's done OK so far.
Fit and Outfitting:
I fit well at 5'10" and 210 lbs. I can brace comfortably and the seat isn't bad, better than any rec kayak I've used and better than the seats in the other kayaks at the demo day. The cockpit is very big compared to it's competition, which I was looking for. You can easily put a camera between your legs without interfering with your legs. I wear size 10 shoes and my shoes sometimes hit the deck when I'm paddling hard. Booties or socks wouldn't be bad, but I won't be wearing my rubber boots this winter. The seat has a problem- their system uses a D-ring to hold up the backband into position. The D-ring that came with the seat stretched and had a 1/2 inch gap after a while. A lighter paddler that me bent it. I replaced it with a new D-ring from Hobby Lobby, but it did the same thing. I then lost it in transport. It doesn't bother me too much since I paddle sitting straight without leaning on the back band very often, but you need to get some replacement 1" D-Rings and have them ready. It's quite easy to replace.
As for outfitting, I have stuffed it's compartments with the following: 40 degree sleeping bag, 3 man tent, cook pot, Jetboil system, 2 days of food, 2 days of clothes, emergency kit, toiletries, water, and other sundries. I had room left over after careful packing. I'd say I could travel 3-5 days if I don't have to carry water. If you get a rudder, don't pack anything in the rear compartment that can't get wet. I was irritated by water getting into the rear hatch and couldn't figure out how it was getting there. Not a lot of water, but definitely use dry bags. The rudder system is the culprit. I recommend sealing every hole in the rear with silicon as soon as you get it. The front compartment is bone dry. I really like how they molded in their T-nuts for outfitting- they don't leak into the hatches.
Water in the rear hatch. There is a place to lay your paddle on the rear deck for wet entry, but there are no straps or bungies to actually perform a wet entry. REALLY dumb. I guess you could do a wet entry on the foredeck since there's a bungeed paddle park there. I'm getting ready to buy some straps to place across the rear paddle park. No rigging on rear deck. That stupid D-Ring problem. Deck height above shoes.
If you want a kayak that is short enough to maneuver on small streams and big enough to pack for a 3 day trip (backpacking gear), this kayak deserves your attention. It might sound like I had a lot of problems, but I wanted to make sure you know the problems before you get dazzled by it's handling and abilities.