NZBGet (Mac OS X) v19.0

NZBGet (Mac OS X) is an efficient usenet downloader written in C++ and designed with performance in mind to achieve maximum download speed by using very little system resources.

NZBGet runs invisible in background and can be configured and controlled from a web-browser (has a separate theme for smartphones). There is also a console interface to use from terminal.
Automatic download, par-repair (if needed), unpack and post-processing. Everything you need to automate your downloads. Powerful RSS filters with duplicate check to fetch and enqueue nzb-files automatically from your favorite indexers.
Third-party apps can communicate with NZBGet using RPC-API. Every feature seen in the built-in web-interface can be used by other programs too.

Multiple news servers with multiple priority levels. If you have multiple accounts on the same server you can group them so by a failure on one server other servers of the same group are skipped (they would fail anyway). Servers can be switched off and on on certain week days and times by the built-in scheduler.

If files need to be repaired NZBGet can significantly speed up the process thanks to unique fast file verification (first stage of repair) and multicore repair supported on all platforms and CPUs.

Many files posted to usenet nowadays have obfuscated file names. Original names must be restored using included par-files. NZBGet has a unique feature called "fast par-rename", which restores original file names within few seconds, even on very slow machines, eliminating the need for time consuming par-verify step.