If you come to Miami, you have to check out Ocean Drive. ONCE. Cool buildings, the beach, sidewalk cafes and incredible people watching.
However you are harassed by all the sidewalk cafe staff to eat at their establishment, the beach itself is kinda dirty (trash) and I would not go at night and it was expensive on ocean drive to eat or drink.
Obviously a party location. I would get tired of this scene if I stayed more than an day.