I recently stayed at this hotel for a business conference that was held next door at the Fontainebleau (FB). Eden Roc is a very nice hotel with a great pool area and access to the beach. The room was very nice, although my view was not great, probably due to being there for work. I only ate at the hotel once at the restaurant near the pool and it was very good and the staff was very friendly. I also appreciated the free beach chairs.
The only downside to this hotel is the proximity to the massive FB. If I had been there for a vacation I would have been annoyed with all of the people. There was at least one conference going on in the Eden Roc and two more next door at the FB so there was a ton of business people at the hotels. This tended to have certain venues closed due to private parties. I would definitely check with hotel about conferences going on before booking for a vacation. The only other negative for me was the location of the hotel which is on the north side of South Beach. There is very little within walking distance compared to other hotels towards the south. Be prepared to take cabs if you don't have a car.
Overall it is a great hotel if you can avoid the conferences and don't mind taking cabs/driving around town.