I’ve been using Reeder 2 for Mac since it was released, and although it’s hard to imagine a better desktop blog reader, the next version is also an Instapaper client, which trumps all of the other improvements (in my opinion).
I grabbed the latest beta last night and dropped it into /Applications as a Reeder 2 replacement. It picked up my previous configuration instantly, and adding my Instapaper account was straightforward. Thankfully I was able to configure manual archiving for Instapaper (this is analogous to marking RSS posts read, which I prefer to be automatic “on-open”) and was able to catch up on most of my “Read on Desktop” folder straightaway.
Aside from a few non-critical UI glitches, this is a very stable beta. Well worth your time.