If you are in Recife on Carnival it worths to go to the carnival on the "Recife Antigo". This spot gathers all the IT companies of the city. During the Carnival the island become a place where you can enjoy all kind of music .. not only Samba, actually Samba is one of the things you might not hear. But you will have chance to hear "Frevo" and "Marcatu" .. two kind of music that you will find only in Recife. But you will also have a chance to hear Rock, Techno, Rap and so on.
It is really cook seeing all that people enjoying and respecting each others.
On my eighth trip to Brazil I finally experienced Carnaval, in Recife and Olinda. There are significant differences depending on where you go in Brazil for Carnaval.
In Recife the music and traditional dance, Frevo, are unique. They are unlike Samba (Rio, SP) and Axe (Salvador). I was a little surprised to see so many large trailer trucks (like the trio electricos in Salvador) creeping through the streets.
The costumes (fantasias) worn by various participants are different too. The Frevo dancers ... bonecos... the Maracatu. And for the residents and visitors in the crowd it takes on a US Halloween flavor, with children in Batman outfits and women dressed as catholic schoolgirls or Raggedy Ann dolls (examples).
Given what I know second-hand about Carnaval in the other places, I suspect that Carnaval in Recife is the biggest in terms of number of people on the city streets day and night for four days. It starts mid-day on Friday and continues through Tuesday.
In an addition to the folia (the parading, the revelry), many large stages are set up through out the city with concerts and other presentations starting in the evening and running until 3AM.
Get into a camarote (reviewing box) sponsored by the State or City and you will enjoy free food (delicious buffet) and drink (beer, whiskey, soda, water) for as long as you are. With free admission. Free, totally free. They are very proud of this fact. Note: Olinda is a different situation. Admission to one of the few camarotes that line the route will cost you about $60 US.
Many people are concerned about safety in large, dense crowds like this. I guess this is prudent ... I look at it statistically: unlikely to happen to any individual and if you're taking precautions this reduces your risk even further. Occasionally there is pick-pocketing, robbery and minor melees. But nothing has ever happened to me in Brazil and I've never witnessed anything.
Recife Carnival may be the best in Brazil. Its unusually early commencement means visitors can catch the opening festivities and still have time to enjoy other Brazilian carnival celebrations.