brie

Depends on your preferences. I am a fan of the JFK routing over MIA, because I like the longer leg on the overnight (and, for me, more time on international equipment, since I connect to a short domestic hop). I can sleep better GRU-JFK than GRU-MIA. A colleague prefers to split the legs at least a little more evenly/reduce length of any one leg. I also personally disliked the early morning MIA arrival (sometimes prior to the opening of security for readmission airside), though it has been a long while since I took that routing and the timing may have changed. Of course, YMMV (literally and figuratively).