The only straight-up comparison I have is with Magic Mountain's Scream, and Kraken remains smoother than that coaster, which went rough within a year. And Kraken's setting blows away the parking lot upon which Scream sits.
A really great coaster. Can't say I agree with it being rough. I rode it in late August and found it smooth as silk. My only complaint would be its loading staff, who regularly allow the cars to begin their voyage with empty seats.
Maybe when I get back to Orlando in 2010 I will get another crack at Kraken!
That said, last week I was at Sea World and rode Kraken for the first time in a couple of years. What a delightful ride. The front row on this coaster is a real treat.
This should be fun :)