Hi!
I lived in the USA 6 for years. On my first Florida holiday I stayed in the Howard Johnson Plaza Dezerland Beach & Spa Hotel, Miami Beach. It was very nice . Some pic:
If you looking for a nice beach holiday in South Florida, Miami South Beach is a good choice.
If you after family friendly places then Fort Lauderdale or Pompano Beach can be better option.(about 25 miles North from Miami) Cheaper, not that busy, no scary places (like the city in Miami sometimes), lots of apartment style options. Personally if I would go back for a holiday I would get a car at the airport , travel around: Key West is very cool, Bahia Honda Island is absolutely nice , a boat tour in the Miami bay area is good ( lot of famous peoples houses) Miami Seaquarium, Everglades National Park ect...(hope this will help)
Regards B)