Like FullWings, I flew an engine where we had an EPR of 0.982 or something equally meaningless (RR Trent 500), since then, I have always preferred N1, not as a direct measure of performance, but rather as a reliable reference I can come back to. I now operate the GP7000 engine which has a EPR variant called 'Thrust'. It's very clever (perhaps too clever), 100% 'Thrust' is exactly that, nice idea but relies on multiple sensors. For an unreliable speed reference, I am still noting the cruise N1 and pitch attitude as my reference in case the clever system becomes confused.