I am seeing this app mentioned after years. When did this one move to subscription model - it was a one time paid app? Found it - it's also available as Reeder Classic on mac app store.
The one-time payment app and NetNewsWire (both excellent RSS readers themselves!) take a different approach than the subscription-only version of Reeder: they treat RSS more like email (with an emphasis on reading everything, or at least marking it as read).
Anyway, there's this https://netnewswire.com - https://github.com/Ranchero-Software/NetNewsWire (mac native) if someone is looking for an open source alt.