This weekend I rented a Cayman for an hour and paddled it on Lake Mineral Wells for an hour--SSE wind of 20 mpg, gusting to 30. The boat ramp is at the south end of the lake. I chose the Cayman as it was the fastest kayak they had, and I liked the look of its bow--quite fine for a plastic kayak.
I am 5'8" and 225, and it fit me well. My legs are short enough the footpegs fit well, and it had the optional seat which was very comfortable. Ten minutes into the trip, the whitecaps started, and it was great fun surfing the waves. Twenty minutes into the trip I ducked into a quiet bay out of the wind. I then headed south into the wind back to the ramp. For 20 minutes I worked very hard for almost no gain, perhaps one mile an hour. If I had not had to be back in one hour, I would have just stayed out and played. Halfway back, the waves reduced to non-whitecap status, and I was able to increase to 3 or 4 mph.
The complaints I have are minor, with the largest being how wet the ride was, but one should expect that in a SOT. If I could find a kayak 2 feet longer and 2 inched narrower, one would have much more speed and not much less stability. I am seriously considering an RTM Disco, affordable and fast. But for a 12'6" kayak, the Cayman was fine and I would buy one as a backup if the price is right. If one has trouble tracking in this kayak, consider your paddling style rather than blaming the kayak.