Ive been to ST the last 2 years, both times had great rides on ST. I ride back seat with slack in the belt and bar up a notch or 2 and I never have a problem with the buckle or the roughness. The only roughness exists on a couple of the valleys going out and to be honest, the only airtime is in the back now. Because of the track getting old and shotty its lost some speed and thus lost the floater air in the front. Now if you want airtime you must sit in the back car. Even the car in front of it doesnt get much compared to just the 2 rows behind. Its quite amazing the difference.
It has gotten a bit rougher since last year, though still not bad.