Oh dear. It seems that for all the promise of a land of joy and wonder the New Xbox Experience was supposed to bring hasn't been fulfilled for everyone. Some, upon updating, have reported various problems ranging from flaky Live Marketplace performance, to bricked console - the latter even afflicting one of our own readers!
According to Larry "Major Nelson" Hyrb "With an update of this magnitude, reaching more than 14 million people around the globe, we are aware some of you may be experiencing a few hiccups along the way," which seems fair enough.
Fixes are being worked on (for those issues that are fixable), though. "The LIVE team is closely monitoring the LIVE service and Xbox.com and are aware of a few issues including what's happening with Marketplace. The team is actively working on the issues, so thanks for bearing with us."
Personally having had no problems I'm more than pleased with the renewed system. It's surprising how fun as simple a task as making an avatar can be. Mine (pictured) looks just like me- ask anyone here at TrustedReviews!
Hard drive installs are an absolute Godsend! Odd as it may sound, I found the lack of drive spinning slightly distracting playing a few rounds of Gears of War 2 Horde mode last night.