This is a pretty old thread, but I'm going to answer and say it has to be the Kraken for me. I think it's much smoother than the Hulk, and I was pretty let down by the launch, I didn't think it was strong enough.
When in SeaWorld at night during the water/light display, my friend and I were able to go on Kraken over 10 times continuously, and were actually wanting to. I think if I'd had that chance with The Hulk, while I would have still riden, I wouldn't have been as interested.