Conversion from one aeroplane to another is always a time of increased difficulty, but having converted, there's no significant increase in difficulty in flying a jet aircraft over flying a propeller aircraft. There are certainly fundamental differences to re-learn, but having learned them executing the different techniques is no more difficult than for the prop aircraft (For example you might find that if low on an ILS approach a hand full of thrust might give you a totally different effect that a handful of power).
Actually, there's a lot of bluff involved, jet pilots usually manage to convince prop pilots that jets are extraordinarily difficult to fly. Having overcome the propaganda and found that they're not, phase 2 of the bluff is that wide bodys are infinetly more difficult, which of course they're not (much easier in fact). Phase 3 of the bluff then advocates that long haul flying requires you to be propelled into the astronaut league, whereas the only really difficult part is staying awake.
Can't wait for phase 4, whatever that may be. I guess that the white gloves shops are doing a roaring trade from the would-be A380 pilots.
Regards,
Old Smokey