Currently flying with both, I have to say I prefer N1. If you’re going off on a 12hr flight, you know 80% N1 is not a good thrust reference (or at least you should double-check) but 1.276 EPR could be OK or not as it is affected a lot by ambient conditions. With engines synched on N1, you don’t get the phasing vibration you get when it’s trying to match EPR giving a slight mismatch in RPM. Even worse with 3 or 4 power units all slightly different.
Lots of different sensors contribute to EPR and there are lots of ways of it being wrong; it is difficult to conceive of a scenario where N1 is not correct but >0, so it’s more obvious that it’s not right. If you have serious blade damage, all bets are off at that point and you get what you get. On my current steed, 0.97 EPR cruises you around at 250kts in some scenarios so it seems to have lost the direct connection to thrust and is just another number. Did I say I prefer N1?