We stayed here for a week while attending a conference held on-site. This is a nice hotel which lives up to its 4-star rating. The rooms are nice, perfectly clean and well-decorated, with very nice and spacious bathrooms. We paid R$471 for a "double executive superior", which seemed a lot for a fairly standard room, but after shopping around we found this is simply what it costs for this standard in this area.
The location is somewhat away from the center of Rio, on the (very long, lovely and rather quiet) Barra de Tijuica Beach. It seems to be a very common site for meetings and conferences so I imagine many guests stay here to attend on-site meetings. However it is still rather easy to get into the center - city buses stop right outside the hotel and reach Ipanema in as little as 15 minutes (just ask at the front desk, that's what we did). Taxis are also very easy if you want to go somewhere specific.
The hotel also offers various city tours, which are rather expensive (if I recall, around R$100 for a car for 4, for a full day) but still much cheaper than those offered by our conference.
The Sheraton which is a few minutes away is a similar standard, so most attendees of our conference stayed at one of these two and there was a lot of comparison. To summarise: price is very similar (the Sheraton was slightly more at this time); Sheraton has larger rooms (mini-suites) and on average better views (although our 8th-floor room had a nice beach view). However the Windsor rooms seems to have slightly better decor and much nicer bathrooms. Also (the deciding factor for us), the Sheraton offers no breakfast, while the free breakfast at the Windsor was an very extensive and very high quality spread. There was good variety of all the standard items (breads, cereals, meats/cheeses, hot items), but quality was definitely above par, the selection of fresh fruit was extensive and there were made-to-order omelettes (no extra charge). We also ate lunch several times at the hotel restaurant (paid by the conference) and the food was very good.
One major negative: the hotel offers wireless (and wired) internet, but it is VERY expensive and more importantly, the signal is terrible. We had difficulty getting a signal at all (on the 8th floor, about the middle of the hotel), it was very slow, we could only connect one computer at a time, and one full day there was no access at all. In the end the internet was not listed on our hotel bill, even though we never complained directly to the front desk (only to tech services).
There was also free wireless on the conference levels (paid by the conference but administered by the hotel), and the signal here was also terrible. Otherwise the conference facilities were entirely acceptable, although fairly standard.
Overall: this is a very good place to stay if attending a meeting or other even in this area. If you are looking for a quiet stay away from the center of Rio (but still 4-stay accomodation), this may also be a good choice. Otherwise, for most tourists there are probably better choices closer to the center.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.