It's awesome. The interface takes some getting used to - the tabs up top are what you need to switch between for mass renaming, altering tags, or generating tags from filenames.
Be warned, though - it gets sluggish if you try to alter too many files at once.
I decided to remove all entries from the "Comments" field in ID3v2 tags from my entire collection (around 5,000 MP3s). Took about 30 minutes and nearly killed my poor computer. And I couldn't stop the operation with Ctrl+Alt+Del and killing the process. Poor hard drive was squealing from working so hard.
