Better than the rest ...
... I think I tried almost every anti-RSI app for the mac over the last years and this is the one I stick to. Eats almost zero CPU time and is unobtrusive enough but still a friendly reminder to give your wrists, shoulders and brain(s, if you have multiple) a brake.
Thanks, dev! I threw away my free version today and bought this one from th AppStore to give some love ...
:)
ProperCroc about AntiRSI, v3.0.2