I have used Newzie for a year but now I use mainly GreatNews (one of the reasons is the fact that GN can be translated, whereas Newzie cannot be at this time). Newzie is good-looking and has some very useful features (for example the List View, that orders the feeds after the date of the last update), but it does have its share of usability problems. One is the impossibility to use an external browser. The developer responds to the e-mails usually quite rapidly, but does not always implement the requested features, although it will offer explanations for that (I wanted the tabs to be closed on double-click and I wanted also the tabs to have shorter titles, so I could open more of them).
There is room for improvement regarding the management of tabs, for example the tabs could be locked in order to not close them accidentally. Or they could be moved, etc. They could also be opened (optionally) in the background. I think I have made at least 10 suggestion like that, but they were not implemented, for various reasons. But all the bugs reported by me were fixed.
The problem seems to be that there is only one developer and it also works on Ziepod (the best podcast catcher in my opinion) and lately on a discussion platform (like a forum, but with audio posts) that was not greeted with enthusiasm.
I always recommend Newzie to the people that do not want to use GreatNews. But I also recommend Abilon ( http://www.softpedia...g-Tools/Abilon.shtml
) , a software that is not developed anymore, but also supports folders. I had lenghty e-mail exchanges with the author of Abilon and some features were suggested by me. Unfortunately he decided to abandon the software because he lacked the time to develop it further. But the program is very stable and can be used without problems even now, even on Vista.
The sad fact is that Google Reader killed many of the RSS aggregators. I dont like GR at all, but many people use it, especially those that are not so habituated with RSS. I think GR became in just a year the most used RSS aggregator software. Some developers could not sell their programs anymore and consequently abandoned them (Abilon had also a paid version, named Active Refresh) or put them on hold for a long time (Newzcrawler).