I fly both N1 and EPR variants and prefer N1 for several reasons:
- There is no easy "ballpark" estimation of what EPR should be for a given phase of flight, as it changes markedly with temperature & altitude.
- On the old generation of EPR-controlled engines, 1.0 meant no net thrust; who knows what it means on the RR Trent, for example?
- Engines that synchronise on N1 are much quieter that those that use EPR as you don't get that horrible phasing vibration in the cruise. Probably better for the life of every other component in the aircraft, too.
- N1 is directly coupled to something physical whereas EPR is derived, so more liable to error/miscalculation.
- One less gauge required.
I suppose when everything is working, EPR can be more accurate but as virtually nothing else about the aircraft or conditions (weight, wind, surface state, humidity, etc.) is known to the same level of accuracy, it's rather meaningless. Gross errors are what get you...