Currently Being ModeratedDec 7, 2012 8:23 PM (in response to ericfromal)
Unless you have explicitely downloaded songs to your iPhone everything resides in the cloud and is not physically on the device. So... when you turn the service off, yes, everything will disappear from the iPhone.
Currently Being ModeratedDec 7, 2012 9:16 PM (in response to Michael Allbritton)
But things WERE on my phone. when connected to iTunes, my phone showed the audio using 11GB out of 16 on my phone. When I would turn Match off, the songs stored on my phone would still be there. I added music back to my phone (Match still off), now I'm dealing with no album artwork. This is very frustrating.
Currently Being ModeratedDec 8, 2012 11:28 AM (in response to ericfromal)
There are two settings - one to turn iTunes Match on and off, and one to "show all music". The one you want to use, usually, is "show all music" - when that's off you won't see any music in the cloud and you'll be more or less limited to the music that's actually on your phone (I think you can still search to pull music down from the cloud).
Turning off iTunes match is more permanent, and yes it does now delete the music (with iOS 5 it didn't, but that changed with iOS 6 in September). You should only use this setting if you want to completely disengage from iTunes Match and go back to syncing your music via USB cable.