I don't think is a private tracker per se, or at least most people don't use it like that. As most servers (all I know) and the Kad network is public.
As a protocol is worse in everyway that BitTorrent.
But it has been used for so long that the amount of antique media is amazing. It's my last resort for when I want to find something obscure that doesn't exist anywhere else.
Also sharing is really simple, and the integrated search makes easy to find stuff, rather than navigate a ton of trackers or try to set up embedded search in a BitTorrent client and have it fail half the time.
It also lacks any essential security features, it's just blind trust based in a filename unless you got the e2k link from a forum. So I wouldn't download an executable from there.