I think it depends on what your interest are. I hear they have better "american like" parties in SP. Rio is one of my Fav cities however so I am going to recommend it. It is also a really beautiful city. Depending on the month you go, there is also Islands not too far from the cities you can visit for a few days that are beautiful. Pretty sure the women in Rio will look way better as well.
Will try to practice my PT.
O restaurante que ele recomendei muito caro, mas tem lugar perto chamada Suco 24. Eles vende sanduíches e shakes que é muito bom.
Pra Hotels, eu posso recomendar
http://www.ibis.com/gb/hotel-5173-ibis-salvador-rio-vermelho/index.shtml , mas eu acho que voce deve usar homeaway.com ou airbnb. Homeaway.com geralmente é mais baroto.