Love the St. Regis Bal Harbour - we went for 3 years during a peak spring break week and it was always warm enough for pool/beach and there were zero issues with a rowdy spring break crowd (not the hotel most will be staying at!). Nice to be in Bal Harbour also as you are removed from the crowds of Miami Beach. Beautiful resort with great/modern rooms, a relaxing adult pool, nice restaurants, and lux service. Beach isn't amazing...has had a good amount of seaweed the past few years, but it does the trick!