JFK-GRU is in a 767, and the flight is 9 hours. It can be frustrating because they don't give you a lot to distract yourself - and the pitch is tight, but otherwise I felt no noticeable difference from the Transatlantic flights I had on KLM in 03, LH in 01 or BA in 98. In fact, I found the service to be really good - and the food not awful.