I downloaded this to see what all the excitement is about. For the record, my knowledge of mastering is limited, but I do know that you should get your recording to sound as good as possible before sending it out to an ME. So far, I'm most intrigued by the spectrum analyzer. I've always felt that my recordings are lacking in a proper frequency balance, so this should be a big help. Not because I want to match frequencies, but because if can hear that something's not quite right with my mix, this might at least point me in the right direction. My plan is to adjust the frequencies in the mix to keep them more in line with the suggested spectrum, and then listen to it from there, not to follow it religiously. I'm kind of looking at it as a learning tool rather than an automated ME. Incidentally, to check the validity of at least the spectrum suggestions, I had it analyze a commercially released song by prog giants Yes. Using the Instrumental Rock file for the reference, the results were virtually identical.