I only went to Leeds for the Saturday but it was mint. Saw a fair few bands actually, some unintentional ones too:
3OH3 - crap music, but not too bad live
Chipmunk never turned up which I was a bit gutted about
MixHell - crap, was really looking forward to these but they were awful (yes he played drums but wasn't anything spectacular)
Brand New - Saw these while chatting to my mates on the main stage, each song sounded the same to me (not my style of music anymore though lol)
The Qemists - First couple of songs were sketchy, last half were really good. A surprise as they've been described as Pendulum-esque, which can never really be a good thing imo...
Lady Sovereign - Disgusting, but brilliant! Had some sort of power failure but she handled it well, big surprise for me.
Chase & Status - Incredible, better than when I saw them in Gateshead, maniacs in the crowd as per, dropped so many immense tunes it was unreal.
The Living Daylights - My mates band who headlined the BBC Introducing stage. Only caught their final song though unfortunately
And the MC bloke wouldn't let them do an encore, despite everyone in the audience shouting for one. The short bit I saw though was really good, good to see some old faces from Lincoln in the crowd too - was a bit like going back in time a few years to Friday nights at The Bivouac in Lincoln there were all the same faces there
MSTRKRFT - First bit was OK, then they dropped their JUSTICE remix and a Daft Punk remix, and from then on it was really good. Ended with Queens Bohemian Rhapsody which was brilliant (bit of a cliché but still good)
Vitalic - INSANELY GOOD! Soooo loud, easy the loudest of the day. We were stood at the very back of the dance tent and the bass was bone shakingly good. Loved the Mirrored-LED-type screens behind him. Highlight of the day for me, as he was as good as Deadmau5 and C&S but managed to hold my attention and had me smiling all the way through his set, without knowing any of his tunes.
Deadmau5 - The reason I went, and he was fantastic. The tent was rammed, and we were sat on the fence at the very back so had a perfect view of everything. He was top notch, couldn't fault him at all. Only downside was a guy came behind our fence and then stood on it and started dancing, pushing the fence forward which made some marshal guy come and tell us all to get off the fence, bad crack. I'm definitely going to go see the mau5 again, sure I saw a poster of him doing a tour later this year? Oh, and he got Rick Rolled to finish the night off -fantastic lol.
Overall, top day out. Was too tired to stay for C&S' second DJ set though so left after the mau5. I was surprised how much I enjoyed it as I've never been to a gig sober before (that sounds bad lol) but it was fantastic.