Apple - What happens if you stop iTunes Match subscription?

You will no longer be able to download like you currently do, and in effect, iTunes will act like Match was never on.

You will be able to keep any songs you downloaded, though. So if you upgraded files you uploaded that matched to iTunes-Plus-type files, then you keep those once it cancels.

You are unable to down- or upload Music to iTunes Match

So be careful:

Before iTunes Match is expiring, download all your Music from the iCloud (iTunes Match).

So, only the music you bought through iTunes is accessible.

Music which you matched through iTunes Match is lost, and cannot redownload on any device. Only the files you have on your hard drive can kept, and those which bought through iTunes.

You will want to download a copy of anything you wish before letting the subscription lapse if you don't otherwise have a copy of the music and playlists on a machine that is backed up.

The match provides playlist syncing, so your iTunes will act just like it does when not connected to the network. You will only be able to play songs that are cached or downloaded locally. I would presume that songs that only existed in the cloud would either be shown as missing or cleaned up and deleted - perhaps with a message letting you know what happened.

I've not found a way to test this yet since subscriptions are only yearly and we haven't gotten to the point where someone can actually have this happen as part of the normal subscription expiration process.