Yes, I agree that new hotels are hard to ignore. For certain though, the Sheraton is much more of a vacation property. Directly on the beach, lagoon style pool, etc. Funny thing is that the pool is not heated, if that bothers you. (Us Floridians would never swim in an unheated pool in March!) It should be quite warm though in March. Location is nice with the Bal Harbour shops across the street, but they are very, very expensive stores.

Mandarin is a business property. Obviously quite deluxe, but not on a beach. On the bay, but no beach. Not much really around there but lots of international banks, and a few good restaurants. It is close to Coconut Grove, and Key Biscayne, which are nice tourist areas. (be careful in Coconut Grove at night). Also near downtown Miami, but not a whole lot there other than Bayside.