I have a pretty modest library. 4,916 tracks, 15d 3h, 33.6 GB. Sadly, I lost all my "date added" tags when I switched over from iTunes several years ago; it would have been fun to chart the growth of my library over time.
MusicBee can be a tiny bit sluggish at managing everything, but I think that's really my fault for keeping 320 kbps MP3s that I could probably downsize without losing any enjoyment, not to mention the massive album art (2000px+, in some cases) that I've embedded in every file. I'm just very paranoid about data integrity, especially after Windows Media Player - which I don't even use - saw fit to destroy half my collection of "folder.jpg" covers.