What are some alternatives?
When comparing GrabIt and NewsBin, you can also consider the following products
SABnzbd - SABnzbd is a free/open-source cross-platform binary newsreader written in Python.
HelloNzb - HelloNzb - The Binary Usenet Tool
NZBGet - The most efficient usenet downloader.
GetNZB - GetNZB is a free Newsreader software with integrated NNTP access for downloading files from Usenet.
alt.binz - alt.binz is a powerful binary newsreader, for downloading and managing articles from Usenet.
Nzbvortex - The small and efficient NZB client for OSX, optimized for performance and ease of use.