As I said, your best means for comparison will probably be to compare mp3s from both MusicMatch and Lame with straight wav files. Personal experience has proven MusicMatch to be noticeably inferior to Lame in my own listening tests. Keep in mind that when I say Lame produces files of superior quality, I do not mean files that sound better, I mean files that are more often indistinguishable from the original cd.

According to my personal notes, I perceived a difference between MM at 100% VBR and the original source 4 out of 10 times. Of those times I was correct in my identification of the MM encoded file 90% of the time. In comparison, I perceived a difference between Lame using --alt-bitrate-standard and the original source 2 out of 10 times, and was only correct in my identification of of the Lame encoded file about 50% of the time, which shows that my detection of a difference in that case was very likely only a shortcoming of my ears rather than of the mp3s.

If you are as anal about such matters as me, and have a friend to help you, I would suggest a series of blind listening tests. Only proving it to yourself will convince you.

And keep in mind that if you can really tell the difference between Lame at --alt-bitrate-standard and the source material, there are still the -extreme and -insane settings.