..there's plenty of good lineups and locations to see good DJs doing their thing. It's not an EDM festival.
Are you referring to Ultra or are you referring to Miami Music Week or whatever it's called now?
Whilst not one and exclusively the same, there is a certain demographic that are in heavy attendance during this time of the year there that isn't for me seeing as I'm a middle-aged cunt. A lot of US colleges have their spring breaks around that time and it's full of 'bro's' and frat/sorority types.
South Beach is pretty horrid of a place in my opinion too. It's very Barbie & Ken, plastic, very expensive and full of Yanks. There's better places in the world to check out week-long electronic music focused events. ADE, BPM, Croatia, etc. There are far better American cities too - New York for instance.