This is an astonishingly powerful and useful program. I have other programs to fix problems with my iTunes songs and library (Media Rage and Jaikoz) but nothing that I know of does the kind of intelligent fixing that beaTunes does.
The BPM, color, key matching/manipulating feature are amazing, and again, unique, so far as I know. This program gives you the horsepower to make some truly amazing playlists, discovering relationships between songs you'd never think of yourself, but when you hear, they make total sense.
The program is easy to use, and fun to use. Some of the features, like determining the BPM for songs, can take time the first time this is determined, but the more you use it, the "smarter" your iTune library becomes, so to speak. You really can make some amazing correlations, and learn a lot about the music you have.
Be warned, though, the program's addictive! You can spend hours having fun with your music and learning all about it. I've made some of my most enjoyable and fascinating playlists with this program, plus beaTunes does all the mundane kinds of fixing that the other song maintenance programs I have do. If you consider the "smarts" of this program, and all it's features, I think it's well worth the price if you're a music buff.