So all in all it's a great idea, as with new product it has some kinks that I hope Thule will improve on and sort out with defects for existing owners.
I researched all over about kayak carriers and was firmly convinced that Yakima Mako saddles would be the best (from customer reviews). I took the $200 plunge and bought the saddles from Marathon Sports in Toronto. At the time the sales lady was very helpful and convincing...obviously selling me on these saddles. Very excited I tried them out with my 17.5 ft boat. I was horrified after getting the boat secured and driving down my street that the boat was moving a good inch or so from the car/wind. I immediately called Yakima and Marathon, and basically was told that I'm stuck with these saddles. Both tried to pin this on my "improper" set up/use of the saddles, and would not allow me to exchange them for something else or return them. (I found it an absolute crock that I set them up incorrectly as I work at a canoe/kayak store and strap boats down on a regular basis.)
So the long and the short of things go with the Thule Hullaport instead - my boat didn't move a hair (even on the highway) and pass over Marathon. Their unhelpfulness and no return policy bites the big one.