N1, N2 and engine start.

[Saratoga]

Any RR engine has the full three-spools layout. Fuel burn isn't an issue from what I have seen, though some pilots claim the RRs put out less power and it takes more time for them to spool up (not an incredibly noticeable amount to anyone but a pilot).

[Nexus]

This may not be a rule of thumb, but my instructor (the A330 driver) says the RR is the best engine, at least for the Airbus. They can climb directly to cruise altitude at MTOW with the RR Trents (?), something they rarely manage with PW and GE engines - according to him.

[Rocket_Bird]

Not to say your all wrong... ive never worked on a turbofan engine myself... I have taken apart Allison 250 engines and Pratt Whitney PT6 engines, but from what ive come across, N1 has always been noted as the compressor (no matter how many stages, or whether it has a combination of centrifugal and axial compressors), and N2 is your power turbine or free turbine, doesnt matter how many spools you have...

[Saratoga]

I have a preference for P&W personally. No matter what we call them, N1 and N2 are always what it is refered to in the cockpit.