Three support chats with Apple Support, an appointment at the Genius Bar ... and, my songs still get stuck at the "processing" stage. Can't download previously purchased or Music Match'd songs via wifi (any wifi) or 3g.
The Geniuses reset it back to factory new condition, supposedly. It still wasn't downloading. Then one of them did a bit of voodoo, clearing the safari cache and web data (shouldn't it already be clear? It was just restored to new), setting cookies to never accept .. and, suddenly, the 3 songs we were watching downloaded. I'd been there for 2 hours and needed to go, so I said, thanks, I'll see if it's fixed. Of course it wasn't. Haven't gotten a download to pass "Processing" since. Tried repeating that ridiculous voodoo to no avail.
So, I am back to managing the iPad like it was an iPod circa 2005 - putting songs on it with iTunes. WHich is a trick once you're using Match. You have to disable music match in iTunes, disable it on the iPad, and then finally you are able to manage the syncing of songs by hand with iTunes.
To make sure it isn't my account that is at fault, I logged one of the store iPads to my itunes acccount and was able to download previously purchased songs just fine ... something I cannot do since the ios7 upgrade. (I wonder if this is specific to older hardware ... an iPad2 purchased two years ago.)
This problem really stinks and it hope that they get thousands of people at the Apple Stores requesting help with it so it will get fixed in the next bug fix release.