I've been using this since before it went free. During the short time last week when it was showing ads, I tried at least 7 or 8 competing programs; every one of them reminded me why I love NNW so much. The interface is clean and simple, and gives me the option to separate the sections vertically or horizontally. Syncing with Newsgator always worked well, and the only difference I notice with Google Reader is that it seems faster. As long as they give me a way to block the ads (and I don't mind paying), this will be my feed reader of choice.
NetNewsWire
Saft