One of the reasons that I choose Kooks is that I wanted a h-pipe. ARH wasn't offering it when I bought mine. I also liked the idea of merge spikes and equal length primaries. And I got a good deal with Jet Hot coating on them.
The downfall for me was that I couldn't install them by jacking up the engine so I had to pay someone to put the car on a lift and drop the k-member. Those equal length primaries take up a lot of space.