well, my experience and use of usenet is kind of limited but the really goud stuff with (mainly) working links can be found on restricted boards. you at least have to register and access is not always open.
then you need an app like sabnzb and a good usenet provider (depending on what you seek).
mirc is or at least was a free irc client but if you get access to a well managed board that has your stuff you will just need sab. and a vpn of course.
if you just surf and search on your own there is a ton of crap, incomplete stuff, wrongly labeled files etc.