First, let me congratulate this ride as being one of the only coasters (yes, I class it as a coaster) to actually give me pre-ride nerves the first time I rode it. Of course, after riding I realized there was nothing to fear!
Superman launches guests 0-100 mph in 7 seconds via a LSM launch system. You are then propelled vertical 400ft, only to freefall backwards at the same speed and descent. The launch is good and makes your stomach tingle, but the climb doesn't seem long enough, and falls rather short of the top of the tower where Superman awaits.
The the best part of the ride is the weightlessness experienced at the top of the track, you get a cool floating sensation, which is pretty unique to the ride and last for about 5-7 seconds. This is a wonderful experience and should not be missed. Sit in the front for the best view.