One of my biggest frustrations with NetNewsWire was that it scaled horribly. When starting the application, it would take several minutes to load -- not to refresh the feeds, but just to load all the feeds. My poor MacBook Pro would whirr away from all the work it took, and if on battery would drain it within 10 minutes.
Simply put, it was the laptop killer. I used it only very sparingly, and only when I needed to cull through a zillion posts for my BlogHer Contributing Editor gig.
But on January 9th, NewsGator Technologies updated the application with a major refactoring. Just check out the change notes:
Fixed a bug that prevented automatic sleep for some people.
W00t!