FWIW the rotate between the GE 767 and RR 767 feels fairly different.
The GE's generally leap of the ground, whilst the RRs feel like your dragging the thing off.
No one can explain why definitively - other than the RRs appear to come closer to tailstrikes than the GE because of this strange difference.
The best guess they can come up with is that for an equivalent (calculated) thrust/derate the 76GEs are generally pushing out more thrust (other thoughts include rigging differences, slower engine response, engine weight). Many guys add a few extra degrees thrust derate (thats poorly worded - but they add thrust) to the RR to help compensate - especially in gusty conditions - as most have a tendency in x- strong winds to want to get the thing off the ground quickly.