This might be one of my favorite places to stay in the country, and is definitely the only place I'd consider staying in Miami. Five Stars IMHO yes, although WITH SOME MAJOR CAVEATS:
As I mentioned in the 'headline' the main reason I like it so much is it's really like a big spa that has some rooms you can stay in. (The hotel itself is fairly small.) The SPA is exceptionally well run, the HOTEL is not. Since the hotel is so small, they sell spa memberships to people who live in the area. So if you go on a week-end, a lot of the people in the spa and outside at the pool will be locals partying, which is another thing I like a lot: I always meet interesting people here. Spa services are pricey, but completely in line with the area. (Actually, if you're staying somewhere else, another nice thing here is if you book any spa service, you can use the pool, etc. for the day, not just the sauna, which would be the case in most other hotel/spas.) And the quality of spa treatments is good. The sauna and steam room are exceptional. As is the pool, which pipes music in when you're underwater. I also like the outdoor mud treatments (including a naked dip into Biscayne Bay afterwards!)
Now for the negatives: check-in is a rather late 4 PM. Even then, every time I've stayed, my room hasn't been ready at that time. It is irritating to arrive at or after the check-in time and be told: "You're in queue for a room." The only saving grace is the spa has good facilities so you can leave all your stuff in a locker and just go straight to the pool. And this last time the front desk person said she'd call me when the room was ready, which seemed like an improvement in the system, only 3, 4 hours later nobody had called me. (Actually, this ended up costing the hotel $, which I'm sure they don't want: since I didn't have a room #, I couldn't do room charge for drinks at the pool, so was limited to the cash I had on hand, which wasn't much...) Finally, as the sun went down, I called the front desk and they said "Oh yeah, your room is ready." So, great. So I figure I'll pick up the keys, and my bags will be in the room (as they would be in any good hotel.) But no. I get the keys, go to the room, then have to go back to the front to fetch my bags. Similarly, I booked a package through the hotel which included a bottle of wine. The wine should've been in the room when I got to the room. No. No wine appeared until I called and asked for it. And a couple of other things I've mentioned before: 1) the rooms do not have enough power: just 2 open electrical outlets, not enough in this day-and-age. (They could remove the TV for all I care, just give me a place to plug in!) 2) They give you nice robes, but no place to hang them: there are no hooks of any kind in the bathroom. Weird. 3) Why don't they service breakfast in the waterside restaurant?
Staff is uniformly friendly, although not always completely helpful.
With that said: I am still giving it 5 stars, which tells you a lot about my overall experience!!