Apparently there is a limit of 25,000 songs not available in the iTunes store that can be kept in the cloud, this makes me think for music lovers with esoteric tastes it might be a problem.
If it's for you I found this comment from Tee1970 really helpful.
I went thru the matching process about a week ago. First stuff I did -
-Created a playlist of all music with a bit rate less than 256 VBR (variable bit rate)
-Updated all "songs" that were actually audiobooks to the correct media type and genre so they wouldn't all get uploaded as unmatched songs and to get below the 25,000 song limit (I had about 32,000 items when audiobook tracks were included.)
-Re-imported a few cds where I had bit rates less than 100 VBR (too low and it won't match)
-Back up the music collection
The actual scanning and matching ran very quickly, was done in about 2 hours for 9000 songs. About 3,000 were in a low quality that could be redownloaded at the higher iTunes Plus quality. I deleted the matched and upgradable songs, then used the playlist to help track progress for redownloading. I did that part over 2 days on and off when i was not doing other stuff.
I turned on iTunes match on my phone after a few days, and it warns you it will replace your music. I have a metered 3G plan, so I didn't want to stream all the time. I selected a bunch of songs to redownload via wifi, but turned off the iCloud-only music. So basically using iTunes match to upgrade all my music, and provide an off-site, always available backup of my music collection. Well worth the $25! Less to put in my regular backups, and less room to take up on my laptop if you want to delete local copies and store the upgraded music on an external harddrive. Used to be that your entire music collection had to be in the iTunes music directories, now very easy to have partials. Would have loved this a few years ago, as I had been purposely burning lower fidelity songs to save space on my laptop. Now you can listen to the hi-fidelity music all the time, with less hassle
