I rode Stinger last year and I was pleasantly surprised to find that it DIDN'T live up to the horror stories that people tell about Invertigos. It was a very intense ride, but I've had more headbanging on a non-inverted Boomerang.
Hydra, I just don't know what its problem is. For years now, it's had this terrible rattle throughout the course, like the wheels are running on gravel! On a hot day when I'm not properly hydrated, it's given me more of a headache than anything I've ever been on except for Mantis. On a good day though, I love the way it's constantly twisting and following the terrain. I like to ride the back row so I can watch the train in front of me. And the JoJo roll performs the vital function of emptying loose items out of the train before it gets up to speed! (Look underneath it sometime.)
Thunderhawk has one moment of violent ejector airtime that makes it worthwhile despite the complete suckiness of the rest of the ride! You just have to know it's coming so you don't crack your ribs...