Lines at the Mummy seem to die down (sorry, no pun intended) later in the day. Saturday afternoon, there was a posted 15 minute wait, but I'm not sure we even waited that long. Never seems to be that long of a wait on weekday afternoons (I usually get there around 5 or 5:30 if I stop over after work). Even at its worst, it doesn't seem to get as bad as the "E-ticket" rides at IOA. Just my personal observation.
Fear Factor Live is definitely worth seeing. It's amazing to see tourists who were walking around the park 90 minutes ago doing really intense stunts; I'm not even a fan of the TV show, but the live show had me riveted.
With Shrek, Mummy and Fear Factor, Universal is 3 for 3. They are doing a lot to turn around what used to be the most boring theme park in Florida.