I wanted to try and get some music for my workouts organized, and recognized I needed something that could report things automagically.
I tried MixMeister -- haven't tried anything else but based on the results I'm starting to think that BPM recognition is VERY primitive. While it generally made some sense, there were many songs on either end of the spectrum (either very slow or very fast) that were grossly miscalculated (the very slow "Walk on By" with Burt Bacharact was listed as 150+, while the very fast Pointer sisters "I'm So Excited" was listed as 91?!).
In general I think whatever algorithm might be getting confused by volume -- there's got to be something fundamentally flawed in this tagging but I don't know where. It kind of reminds me of the very early days of OCR where the errors made the process hardly worth doing.
It may still be somewhat useful, although I will obviously have to go through the songs manually (10K+ songs! Sigh) and correct the obvious errors. And I may try some other programs just to see if anything is better. But at the moment I think all of these things should be taken with a LARGE dose of salt.