Miami has alot of crime. Do some homework and i suggest check out Aventura and sunny isles. South florida has some very dangerous places. You will need to pay alooot of $ to be in safe neighborhoods here. Everything down here is way over pricced.
Depending on your budget, good "walkability" close to the beach would be Miami Beach, Key Biscayne, A SFH always does better than a condo. When you're ready to find a great real estate agent, I'm ready to apply for the job.