I had the large Sirius, and I'll add to the growing consensus.- not a great kayak. My belief is that the high volume version is dramatically different in the water than the small, and that most of the people that like the Sirius have had the smaller version.
It is not a fast kayak. I've owned and Orion, Explorer, and Outer Island, and all of these kayaks are measurably faster using my motor power. The Orion was 23 inches wide and it was like a bullet compared to the much narrower Sirius. Hmm. Perhaps there is more to hull resistance than hull width...
It is tender. The deep v wants to sit on one side or the other, very good for your bracing skills. However it does settle down nicely when loaded for camping.
The best thing for me was the seat. This is the ONLY factory seat that I have ever approved of. (I cut the seat out of my Explorer after 5 minutes in the kayak).
Had to get my 3 cents in. Good luck!
The Connyak BBS