I stayed at the FS Buenos Aires for 5 nights in late October in one of the larger Premier Rooms. As expected the service was excellent, the room lovely and the location perfect. The concierge and front desk staff were particularly helpful.

One caution: Evidently many of the Premier rooms have adjoining doors to other rooms/suites. I moved to another room after one night because of the noise - TV, conversations - coming from the other room through the closed adjoining door. The management has told me they are looking for better insulation,but I would avoid the adjoining door rooms for now.

But this is a fine hotel.

My wife and I spent an early November week at the B.A. Four Seasons and were awed by the quality of the service. We stayed in a deluxe room at a rate of $430, which included a complimentary breakfast and one massage. We are in our mid-60's and were in B.A. on vacation.
The Faena and the Hyatt Palacio Duhau are more stunningly luxurious, but the Four Seasons is more than sufficiently sumptuous. The room was large, and the bath very spacious and well finished--large walk-in shower with massage-like water flow, marble walls, separate water closet with toilet and bidet. Furnishings were a pleasing up-to-date blend of the traditional and the transitional. Closet space is commodious. The only qualification is that our front 7th floor view included too much of the dingy railroad station and train yard. Rooms on the south side, however, have attractive views.
The staff could not have been more amiable, responsive, or professional. They're all clean-cut, sharp, and attractive, and they continually inquire about how they can be of assistance. The staff complement is more than adequate to handle peak demand. The concierges went to some lengths to set up dinners and entertainment at high-demand spots as well as little-known gems. Their flow of voice mail and written communications was timely and extensive.
My wife had a worsening upper respiratory infection, and when I asked for a doctor, the staff had an MD in our room within 20 minutes! The doctor did a capable job of diagnosis, treatment, and prescribing. Medicines were delivered to our room within 15 minutes!
The breakfasts were lavish--all sorts of meat, cheese, pastries, beverages, and garnishments. Whatever we custom ordered [such as a white egg omelet] was prepared quickly and with flair.
Maid service was frequent during the day and timely. The maids even found our PJ's and put them at the foot of the bed perfectly folded.
There was a large complement of bellman and door service staff. They spoke excellent English and anticipated our requests and needs.
The guests were a true international mix, and most appeared to be at the hotel either individually or in very small groups. The clientele were a polite, up-scale mix that fit in with the progressive general ambience.
Overall, this was the best hotel stay we have ever experienced.

I would have given this 5 stars if the pool was working. I love the hotel and the service at the hotel. The problem was that it was out honeymoon and the pool was not working - it had not been working for some time and the hotel would have been aware of this when I made the booking (I directly called the hotel). The offered to pay the taxi ride and fee for using a pool at another hotel but this was not the same. In summary I had been looking forward to staying at this hotel again but was wish they had informed us of the pool situation.

We stayed in five top hotels around south america during our recent 16 day trip, and this one stood out for its excellence in every way. The rooms are very generous (great shower, great sized bathroom and bedroom), all facilities are as you would hope, but the staff are worthy of special commendation. Each and every one was helpful without being intrusive, knew our names from early in our stay, and were exceptionally polite. The concierge desk is the one other hotels around the world should aspire to. Whether it was booking restaurants, sorting out our flights or transfers, the desk did it with magnificant efficiency. An absolute joy to stay there, worth every penny, would recommend to anyone and other "five star" hotels in Argentina and Brazil should send their heads of staff here to train!!