Being British i naturaly prefer the Rolls Royce engine. Although on the 777 i think taht that GE have a better engine than RR, the fact GE cover the whole 777 family it is also better at cutting matinance costs with its similarity.
On the 757 I think the RB211 is a far superior engine compared to the poor, underpowered and not as reliable P&W alternative.(If you could call it that.)
So GO!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Rolls Royce and Dominate the World!