I have started using GreatNews and so far so good. I am relatively new to using RSS readers, so I am unsure if it's missing any major features. This app runs native and doesn't need Java or .net which is a plus for some folks. I like the "newspaper" type view where I can see the article summaries all at once.
I used RSSOwl previously, which required Java.
Another one I came across, but have not tried, that seems pretty good is RSSBandit. It requires .net.http://www.rssbandit.org/