The seat back is VERY uncomfortable for me, and I noticed that in the store right away. I will be replacing it with an anatomical seat back (about $60) immediately. I am not sure why Mainstream left the seat back all plastic, while the seat bottom has the a padded layer attached. It is brutal.
The size of the cockpit is nice. There are a variety of sprayskirts (both rec and touring) to fit it.
The hatches are expansive, but I did notice some leakage. About a cup in each after a few hours in the bay. I am not sure if it is due to the seal in the bulkheads, or if it is coming in through the lids. I am going to seal the bulkheads with epoxy and see what happens. I decided to take it in the ocean as well (sans sprayskirt and rudder). Dumb idea, but I got excited. It took the breaking waves beautifully, and tracked perfectly on the way out. I stayed out a few minutes and then rode a wave in. It responded sluggishly to paddle ruddering, as expected due to it's length, and I was quickly tossed. This is mostly due to my inexperience in the ocean, but it was really fun anyway.
Now for the cool part. I called Mainstream and found that Perception, Dagger and Mainstream are all sister companies, and the Biscayne is an exact copy of the discontinued Dagger Savannah. So, the Savannah has an optional rudder. Therefore you can put a rudder on the Biscayne. They did warn me that it would void the warranty immediately, but it is only a year anyway. I plan on adding a SealLine SmartTrack Rudder system next season and tackle that ocean again.