I think I've finally found a decent RSS browser. Vienna is an open source client for Mac OS X that satisfies all my must have items, including newsfeed aggregation, OPML import and export, easy keyboard navigation, and more. There are no obvious bugs or user interface glitches.
In one respect, it even exceeds my requirements. I had asked for a browser that hides all read news items, which it can do. However, it also lets me delete news items individually. Thus I can save the items I may want to reread or come back to while deleting most things so I never see them again. Very slick! It also has a significant AppleScript dictionary. It's hard to judge the quality of such a thing without actually writing a few scripts for it, but it looks better than most commercial products.
Vienna isn't written in Java, so I probably won't be able to contribute much back; but on the other hand I'm not sure I need to. It works pretty damn well out of the box.
