The reviews below are old, and in my opinion, do not tell what this application is today.
Having been a windows user for some time, then linux and finally moving to OSX I needed an NZB program that was familiar to me, that monitored my download folder, repaired / extracted everything, allowed multiple server connections SSL, and to have good support.
NZBdrop ticks all the boxes for me, I've requested improvements/ features in the past, and have had quick responses followed by updates with those requests....
Version 3.0 has just been released, and even though there were great improvements in the previous version, this version is now exactly how I need it.
The user interface is tidy, clean, and not bloated with crap which other applications suffer from.
As for the price.. its a very small price to pay for what you get.
Those of you that have moved from windows, and have failed to find an alternative to newsleecher, look no further.
Those of you who have perhaps tried it in the past, and didn't get on with it, or have never tried it at all, the demo is FREE to try, with all the features, you've nothing to lose.