Phil, I don't currently own an Alpacka. One of my best friends up in Anchorage owns one and uses it to run whitewater. He's an animal - rock climber, big wall ice climber, marathon runner, competitive skier, Class IV and V kayaker, etc. He has lots of outdoor experience and when HE says that the Alpacka rafts are serious pieces of equipment I listen.
I'm thinking about getting one because the high-mountain valley where I moose hunt has a braided stream that runs through it. If I take a moose upstream from the landing strip I can carry a 5# inflatable raft/boat and then use it to line heavy loads of meat downstream back to camp. At least that's the idea I am considering.