Hmm, think I'll give it another go. I had it when it first came out but it's matching algorithm was pretty poor. Also sent my ISB bandwidth through the roof.
Just curious where your music came from.
iTunes Match only matches if your music is on the iTunes Store. Many classic CDs have been re-released over time, and your version may not be on the iTunes Store. Typical problem with Beatles, Genesis, etc. Many CDs come in different versions in the USA and Europe; typical result is a CD where everything except a single song is matched.
All in all, 85% of my music was matched. And that included songs that I manually imported from LPs. And what wasn't matched got uploaded, so there's not really a problem. You just don't get the upgrade to 256KBit AAC.