Fingerprinting

I've downloaded last.fm's fingerprinting tool, currently in beta. If I understand it correctly, it will scan my iTunes and take the metadata, mingle it with everybody else's, the end result being better than the sum of its parts.
This seems to me a thoroughly good idea. I have long been frustrated with the uselessness of the Gracenote database iTunes relies on. It frequently confuses artist and composer. To take an example, matching my CDs of Bach's Well-tempered Clavier performed by Davitt Moroney with Gracenote produces some entries that are fine, but some in which composer and performer are transposed. Only some track titles give title,  book  and number,  key and  BWV number. And so on....