asym sidecuts are supposed to compensate for the different amounts of pressure you can generate between your heel and toe edges.
I have never ridden a board with that type of sidecut but snowolf seemed to endorse it earlier in the thread and other people say it works.
While I think the theory for different sidecuts for toe and heel side (Note: this does not necessarily mean asymmetrical sidecuts, just different ones) has some merit, it really made no difference to me in practice. Tried it on the Riders Choice and actually preferred riding the board the 'wrong' way around. Maybe I have grown so used to (over-)compensating for the same sidecut on both toe and heel edge that I need to 'unlearn' first...