We had a great time in South Beach, Miami, Florida! We brought our kids and stayed at a hotel called the President (formerly Penguin). It is located on Collins and 14th in Miami. It was a great location for us. There are some homeless, vagrant type wandering around but everything was fine for us. Overall, we felt safe and could focus on having a good time.
We drove from DisneyWorld (Orlando Florida) to Miami which was about a 4 hour drive.
We were walking distance from the beach, clubs and restaurants. The area was suggested to us by a Miami local and it was a good choice. Walgreens was right across the street.
Parking is pretty expensive especially on the weekends, but we found a place to park for the full 3 days for about $135 dollars. It is normally about $15 dollar/hour. There is a great variety of food on Washington street, which is also walking distance.
Overall we had a great, great time and could definitely see ourselves going back.
Miami Official Page