I turned on the iCloud music option on my ATV after subscribing to iTunes music match, but now want to turn it off.
I get my music directly from my computer (which is always on). In my case, it makes no sense to download music from the internet (from iCloud) and increase my internet usage charges. Plus the navigation of my numerous playlists is slower using iCloud than directly from my computer.
There is no obvious way to turn it off! It's not a huge deal, but a little annoying.