Brazil is AMAZING.
If you stick to the touristy areas, you will be fine.
The main going out area in Sao Paulo is Bela Vista. It has a scene like I've never seen...the one main street is full of bars where people in their 20s literally just hang out outside and drink beer or caipirinhas. Thousands of them.
Historically Rio is the main tourist destination for most (many other South Americans visit the beaches in Southern Brazil like Florianopolis). I spent most of my time there, but I can give you a lot of other general tips.
DO do a favela tour. You go during the day with an English speaking guide. It will be one of the most memorable parts of the trip, guaranteed.
DO just grab beers and street food. Beer is like R2-3 which is like a buck and change, Brazilian beer is good and they are obsessed with serving it as cold as possible. Good street food is a kibbe, which is similar to the Middle Eastern kind but with cheese. Caipirinha is maybe like R4-5. Walk on the street with it, it's legal.
Do try the following food:
- Feijoada, the national dish of Brazil, a stew with various meats and beans.
- Sushi- Brazil has the most Japanese people outside of Japan. Best sushi I ever had was in Rio, and it's probably even better in Sao Paulo as most of the Japanese community is there.
- Rodizio (duh)
- A good Brazilian sandwich like a misto quente
Sao Paulo is gritty, but really, I was not scared in Brazil even once. I went on the favela tour, walked around at night, carried money...if you don't attract the wrong attention in NYC, and don't walk around Brazil with a Rolex while drunkenly screaming in English, you are unlikely to encounter problems. Myself and all my friends who have been to Brazil all feel this way.
It helps if you speak Portuguese, or at least learn a few words, but Brazilians are super nice, they will pretend to know a few words in English or try to switch to Spanish for those that speak it. Sao Paulo is a world city, most Italians and Lebanese outside of their respective countries along with the Japanese, and that will be reflected.
I don't know much about Vitoria, but there may be some beaches in Espiritu Santo worth visiting so I would look into a night or two there as not going to a beach in Brazil is like going there and not getting a steak.
And try not to let your girlfriend catch your eye because it will be on the women there, easily 75% of the women would be 9-10 in the US.