I have paddled these boats, but not in rough conditions. My impressions of all the Tiderace boats is that they didn't feel as good to me as they look. I didn't like their seats, but I'm sure it's like most boats--it takes a while to get used to them. My honest impression of all the Valley and Tiderace boats I have paddled is that the Nordkapp felt better by a long ways than all the rest.
That probably isn't much help.