By all means go to Brazil, but ten days is too long in SP. Hop over to Rio for at least half (or more) of that time, or down to BA. Rio possesses one of the most stunning physical settings of any city on earth, and the Cariocas are drop dead gorgeous, as if you needed an additional reason to experience Rio and her charms BA is affordable and fascinating, among other things. Some time in SP is fine, but definitely branch out if you can.