The shop I work at had a C16 in the demo fleet, and I have taken it out in enough different conditions to convince me to buy one. It's maiden voyage was on a day with good sized surf (6ft @ 11sec), and it lived up to my needs. It better have, 'cuz I sold an Elaho to get this.
First of all, my needs for the boat are specific. I already have an all-purpose boat (good in rough water, great for distance with gear), the C16 is for a day/play purpose; I prefer 16ft boats for surf and rock gardens.
The C16 did very well. Stable, but still easy to edge, very good in winds, and unusually nice in the surf zone (good reserve buoyancy in the bow, stern holds its line on a break= low issues with broaching). Despite a few poundings, the compartments stayed bone dry.
I have had the demo boat out in 25kn winds, and it was easy to control, without resorting to the skeg. The adjustable thigh hooks fit me well, the seat not so well (but that is a personal issue, I am taking a molding off the seat of my sprint boat to replace it with), although the Velcro adjust on the seat is nice. The seat frame on the demo was painfully tight, my new boat has the wider frame- still tight on my large American butt, but acceptable.
Deck rigging is very nice, about time another American manufacturer gets up to date on this issue. Not sure if it was intentional, but the perimeter lines were not strung like piano wire (too common on some American boats, they are missing the point), so getting a hand under is easy.
The good wind handling does come at a cost, the boat is somewhat stiff for a 16 footer. Also, the volume/footprint that makes it so nice in the surf makes for quite a bit of wetted surface-the boat is slower to accelerate than, say, a Romany 16 or a Tempest 165. The low windage means very little pack space (again comparing to the mentioned boats).
All in all, a super fun rough water play/day boat that is very forgiving.
(I think an 8 rating is high, I have yet to find a boat I would rate a 10)