I haven't done Hypersonic, so for now I'm going to say Doctor Doom. Although it's shorter than the others I've ridden (Power Tower and Scream) I like the way you get shot up as well as down. You get a lot more air at the top that way. The theme makes it more exciting too.
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"If we built a ride that everyone wanted to ride, it would be called an elevator, and that's not an amusement ride."
-Stan Checketts, S&S Power