would have said the RB211's were actually harder to start than, say, two-spool CF6's. The RB211 powered 767 even has extra ground cart connections because it is so difficult to start the engines. I would have also said that the CF6 accelerates quicker after light-up (fuel on).
Rgds.
NSEU.
As a licensed engineer on both RB211 and CF-6 NSEU has got it spot on.
matkat