Wow, an old thread comes back to life
OK, starting (must have missed this first time around). In general, the PW4000 was harder to start than the CF6-80C2. It was standard practice to spin the PW4000 up to close to max motoring before putting the fuel on - the CF6 you could turn on fuel at 15% N2 and get a reliably good start. So the Pratt took more air to start. When Boeing built the LCF (aka Dreamlifter) for hauling around 787 parts, they removed the APU (putting a fuel line through where they spit the fuselage to load/unload was too big a challenge), so ground carts were needed for starting - turns out it needed to be pretty good ground cart to get enough air to reliably start.
EPR vs. N1 is a long standing controversy. N1 has a huge advantage of being an easy measurement relative to EPR which requires reliable measurement of two pressures - one in an area that can be prone to icing (inlet EPR probes require ~ 500 watts of power to heat - which also makes reliable temperature measurements tricky). OTOH, EPR is better related to actual thrust - and the thrust/EPR relationship is pretty much constant (TO EPR is pretty much constant below cornerpoint temperature). N1 has that whole messy square root of theta temperature meaning thrust set N1 changes with temperature.
Wiring (and to a lesser extent plumbing) - Rolls certainly looked like it was designed. Pratt and Rolls both just sort of added it when everything else was done - it looks like a mess.