Out of the three, have only stayed in the Four Seasons and it's an excellent hotel. However couldn't get a room earlier this year and stayed at the newish Bairro Alto, loved it, and haven't been back to the FS. It's small, 55 rooms and right in the middle of things, service is above excellent.

FYI, the lower category rooms, those below and including some in the superior level, are small by American standards, which doesn't bother me, but I know is important to many.