Put simply: Music you've uploaded or matched in iTunes Match is stored in the cloud and will stream through Macs and Apple TVs... but if you use an iDevice (iPod Touch, iPad, iPhone), the music is DOWNLOADED to your iDevice and played from there. (Apparently streaming through iDevices was a feature of iTunes Match until late in the beta process, when it was abruptly removed for some unknown reason.) For me, this is a dealbreaker: I signed up for iTunes Match precisely because I wanted to stream my large music collection through my iPhone and my iPads. If I had space on these devices to store downloaded music, I would have synchronized it there in the first place -- as it stands, I'm already short on space and don't need to be worrying about running out. I've called AppleCare and explained this to them, and they've refunded my $24.99. When Apple puts the streaming-to-iDevices functionality back into iTunes Match, I'll sign up for it again.