It is a very general thing to say theirs is better than another design. Jay Babina already said it well. Everything is a tradeoff. For large swells like I deal with I would certainly prefer some rocker. The longer flatter keel would have more tendency to pitch-pole coming down a wave. I am not as concerned about speed going up a swell as I am about not burying the nose coming down it.

That said, there are things that are correct in this article. You do want a longer waterline and you do want to keep the buoyancy evened out (as much as you can) from bow to stern. (Generally stated- in some cases like a surf kayak it's not always the case.)

Here is how I addressed the desire for long waterline and yet have rocker for taking swells. This is an offshore SUP that has a unique vee hull. I am sure if you visit here often you have seen my posts on this. Notice that the bow is vertical, and the keel very straight, but on the outer edges of the hull there is curvature (i.e. rocker) built in so that you get a long waterline in flat water, but the hull still takes a swell fairly well. The lighting doesn't really show it as well, but look at the lines of the strips an you will see the greater curvature on the outer portion of the hull. Coming down a swell the tendency to pitch-pole is offset by the lift created by the shape of the hull. Of course being an SUP, you also have the option that you don't have in a kayak of shifting your weight aft when down-winding, so this is considered in the design. There is much more area aft than forward. For a kayak I would move the CG up and even out the buoyancy front to back, but you see the idea here. Anyway, the whole thing I am saying is you can't just look at the hull profile and say a boat does or does not have rocker. You have to look at the whole 3D hull. Even in this hull I had to make tradeoffs with speed versus rough water handling.

I think Reg Lake needs to take them up on their offer with his latest design for Sterling Kayaks. http://www.sterlingskayak.com/ Note that they say the challenge is rough water handling, not speed. I think Reg needs to take them to Skook and see who makes it out alive.