I just acquired a license for this program, and I'm quite pleased with it. As others mentioned, it's written in Java, but I must say that I don't find the program particularly slow. The fact that it's multiplatform is a great advantage for me since I use OS X and, to a lesser extent, Windows, and I find it great to be able to use the same app on all these platforms.

It has all the options an MP3 tagger and organizer needs, and maybe even more.

Although the program isn't without its downsides (I have experienced some "unexpected errors" and alike), I think it's well worth its price since overall it's a great program that does what it should do.