I've played around with Dave Winer's River 2 and River 3, but ultimately these solutions are expensive because they require a server to process the RSS feeds included in an OPML file. (Here's Dave's River so you know what it looks like.) I used to run my River using EC2 for Poets and the Amazon Web Services bill was way too high just to publish a feed reader.
Like the OPML Editor River of News, there are no bells and whistles here. You can't read full feeds within the "app" or 'Send to Instapaper' or star an item to save it in Pinboard. But it's a good way to just view headlines from your favorite feeds. And because it's a static app and the work is done in the browser, you don't incur server costs beyond just hosting the files somewhere.