I only started using iTunes match so I could get some of my music to play inside an app (Zombies run).
Now I seem to be having all sorts of problems with music I KNOW I paid for, but will not sync, and iTunes "can't find the license". Some of this music was downloaded through non-iTunes sites (paid), and some was ripped from CDs that I own. It seems I have to re-rip from the CDs now...
Also -- I have recordings of conference audios. These will not be available in the cloud, because they are not publicly distributed. According to this thread, I will no longer be able to sync these recordings in order to listen to them on my iPod touch.
Some of my playlists will not upload at all, because they supposedly contain things that "are not music". What these things are, who knows, because i don't see anything but music.
I'm also getting mysterious symbols ... dotted circles, exclamation marks in circles ... no idea what these mean. (So much for the intuitive interface.)
I'm actually rather sorry I put Match in place ... solved one small problem and caused a bunch of bigger new ones. Plus is taking a huge amount of time to figure out what is going on and address the issues.