I've been waiting a very long time to post this mainly because I was expecting so much from iOS 5.1, but I'm still seeing the same issues, and unfortunately, I haven't really seen any others with these issues. So I signed up for iTunes Match, mainly to upgrade my library from old imports from Windows Media Playing using *.wma files, low bit-rate imports from my old old laptop (128kBps), to sync all my devices together automatically (I sometimes purchase from Amazon due to lower prices), and to just have a backup. Well, I know the start was a rough start for many people. Songs not matching, uploads failing, etc... but I didn't really see anyone having issues with general performance and stability on their iOS devices. It started bad for me on iOS, and really hasn't improved. Basically, whenever iTunes Match is enabled, my performance goes down drastically, the network connection is ALWAYS used. Here's a more detailed list: 1) Since iTunes Match, my data usage has doubled, and I don't download over 3G, nor do I have any remote-only files. I download them to my iPhone over WiFi, so why is it eating up over 1GB of data? 2) Music application skips songs randomly, even mid-song. 3) Songs become mislabeled. For example, the song can read "Down On Me (feat. 50 Cent) by Jeremih & 50 Cent" but will actually be playing "Hey Jude by The Beatles". This cannot be fixed unless I remove all the songs, and resync them to my MacBook Pro. 4) Springboard Crashes randomly while playing music. 5) Kernel panics 6) Freezing 7) FWIW: All of my album art doesn't show up, but I know that's a known issue. EDIT: 8) Apparently it keeps on forgetting my iTunes match password because it continually asks for the password. The kernel panicing and freezing just started today while I'm downloading some newly added songs. Here's some debug information: Kernel Panic 1: Kernel Panic 2: After the 2nd Kernel panic, the phone refused to boot all the way. It froze at the Apple loading screen. Holding down the power and home button restarted it again, and it booted up normally. I would include the Springboard crash reports, but they're too large. My iPhone is not jailbroken. For every iOS update, I have completely reset the phone, and set it up as a new phone, and didn't import anything from an old backup. I did this to try to prevent iTunes Match problems. This isn't the first problem I've had with iOS on this phone. With the last version of iOS4, I was having tons of reset and freezing issues, but they all went away when I did a full reset on the phone and set it up as new. Maybe I have a defective phone, but I'd like to hear what others have to say.