For those going, I would add a few that aren't on JDawg's list that might be worth checking out:
Friday
Local Natives
Foals/Big K.R.I.T. (they're playing during Grizzly Bear, which is a tough call, but GB is better indoors with heavily controlled acoustics in my experience)
I don't know Wolfgang Gartner, but that Superjam looks SILLY
Saturday
Cults (don't know Clockwork, but Cults would be worth a look)
Lord Huron
Four Tet (Portugal the Man and Tallest Man on Earth are both tremendous options, but I wouldn't miss Four Tet for the world. my favorite electronic artist.)
Beach House (though Bjork is quite a spectacle live)
Mumfords canceled, so I'd go Preservation Hall unless they promote another (almost certainly better) headliner in mumford's place
Sunday
Kacey Musgraves (it's straight up pop country, but her album is awesome)
Delta Rae
Baroness/Wild Nothing
I'd go to Swans over anything else, but if you did Baroness > Swans, your ears would never work again
Just an incredible lineup overall. Remarkable how much it has changed since I went in '06.