I've been there (Brazil) a couple of times and loved it. I haven't been the Recife, just the larger cities on business. I would think the larger cities are more dangerous. I felt safe, but I took taxis everywhere I went at night - walked during the day, and I avoided the seeder areas.
Go and enjoy. Brazil is one of my favorite places in the world. The people are fun and friendly. Wish we had a little more of that attitude here.
I took my magic case with me (I'm a bit of a magician - henst the handle) and would do magic as ice breakers. Try getting a case of magic tricks through customs I also speak a bit of Portegues - it helps ALOT!
I would lean to MF over LF. Mobilty in a foreign country is never over-rated.