Reliability?

[SanderM2]

In the readme I read "PinChangeInterrupts might be a tiny bit slower and not that reliable because of that detection overhead" which makes me wonder if I can still use it for the following project:

1. I need to count pulses from a flow meter, to measure the amount of fluid passing per minute. (133 pulses per liter, max speed 90lites / minute).
2. At the same time I need to monitor an optical rotary encoder so the pulses from that needs to be accurate but these pulses are low frequency only.

I started on the project using the PunChangeInterrupts library but reading the fact that you call it less reliable makes me wonder if I'm using the right library :-/