Well thank you all very much indeed for your input. ^

The extra problem for me is that the flight is between GRU and IAD/JFK...I understand this is an appauling route for turbulence....Is this generally the case? Like to have a nice friendly crew in these circumstances..

I must say from looking at various videos and reading trip reports, I prefer the look of UA's seat and IFE system.

Tough choice this one...very tough indeed....