Not sure if Ultra Music Festival's lineup is complete, but more acts were added. Organizers added The Bravery, Eric Prydz, Junkie XL, The Veez, Monk, Galaxy Girl, Les Schmitz and Brian Cross to the Day 1 lineup. In addition, I guess the hype around Deadmau5 reached Ultra organizers as they bumped him up from the Dance Rock Stage to the Main Stage. Day 2 sees the additions of Uberzone, The Freestylers, Hydroz, D-Lerium & Phaze, Brazen, Autonomous Bass Heads, Killa Kela, DJ SS feat. Green Law, Sub Focus, Simon Bassline Smith, John B and DB. Also you may want to look over the Day 2 lineup as some acts have mysteriously disappeared -- although none of them I would consider major acts.
If this is the final lineup, Day 1 is clearly the winner here, although Underworld and Calvin Harris on Day 2 are tempting to me. I also sort of refuse to believe the best headliner Ultra organizer could get for Day 1 is Tiesto; there has to be another announcement waiting to happen.
Now all that is left to do is for Ultra to offer damn day passes!