The thing about Primevil Whirl is that it's pretty jerky.
There is a similiar ride at Waldamere park in PA and I LOVE that ride, it's very smooth and really fun, but the one at AK isn't all that smooth and it does jerk you around a bit...it isn't all THAT bad, but I sure
don't consider it a "MUST do" though. I can take it or leave it and wouldn't recommend it to anyone with a known back or neck problem...again, it isn't THAT bad, but it's not worth risking a day a back or neck pain.