The blackwater 10.5 is a very good, versatile boat. I paddle a number of waters; lakes, ponds, swamps, rivers, and some whitewater.
On flat water the blackwater may not be the fastest boat but it tracks well with the skeg down and is very stable. With the skeg up the boat becomes very maneuverable and responsive.
I've taken this kayak on class II, and II+ waters with no incident, but I wouldn't take it down anything more than that. If you plan on doing any class II, do yourself a favor and pickup a skirt. The boat will take on water from waves splashing over. I ran the boat with a skirt, and felt confident and safe on the ww.
The seat is comfortable,is foam padded, and adjustable. The dual density dry storage stayed dry.
All in all the blackwater 10.5 is a boat you won't outgrow quickly, and can be taken on a number of different types of water. Not the fastest, but very stable, tracks well with the skeg down. Being a shorter boat it is easier to maneuver, and is responsive with the skeg up, which is great in mild white water.