I admit to a slight bias, as I am an interval owner of this property. We just stayed for the first time at the Fierro, a boutique hotel in Palermo Hollywood.
http://www.fierrohotel.com/hotel-overview.html It is well located, near to subte, quiet, and very beautifully appointed without pretense. Staff will do anything for you, and the Hernan Gipponi restaurant (apparently #1 on Trip Advisor) as well as the hotel have won several awards though both have been open for only a bit over one year. The owner/developer is Danish, so it even has a sauna near the rooftop pool, as well as little extras like an espresso maker in the room, robes, drinks near the pool.
Now, for FTers the downside is no big-chain points; the upside is: not the same ol' same ol' (insert chain here). Hey, you're going to see the world; why not see how they (insert nationality here) travel in luxury?