Well, since the question was what is your favorite out of Kraken, Hulk and RnRC, I will answer that (just mentioned that because I think Dragons should be in there). First of all, I have not ridden RnRC yet (I will in a few weeks) so I will leave it out.
And now, between Kraken and Hulk, I say the winner is Hulk, almost easily. Although Kraken is a great ride, I prefer Hulk anyday... Hulk is so amazing, IMO. Every part of the ride is great. Initial launch is top notch, the first huge inversions are amazing and the entire ride is non-stop and full of great speed and intensity. For some reason, however, Hulk just stands out in my mind. It has something to do with the whole IoA atmoshere and the area Hulk stands. I love it there so much. One of my biggest memories while riding Hulk is when I was going through the turn around the lauch tunnel where you kinda go over the midway, and I could smeel the pizza down below at the Cafe place. That was sweet.
I dunno, maybe it is just IoA itself that I love so much. One way I sometimes compare coasters is to use the "parking lot factor" Place each coaster in a massive parking lot with no themeing or anything, and which would I rather ride?? Hulk still wins for me.