I've had mine on the river few times. First few trips it had me over more than I would have expected but a quick mess about with the seat position has sorted this. What I did learn though; Man this boat is easy to roll! I took it surfing in the Ocean and it handled big (6ft plus) surf very well with a surprisingly easy paddle out due to lots of rocker.
I'm at the lower weight end for the 7.1 and I do find it a bit bouncy but other than that a nice all round boat that will get you where you want to go and allow you to have some fun on the way.