The security has been shrunk. They also print on areas that normal dvd burners do not print too but can read. At least thats how I understood it. The exact same disk/dvd as is currently used. ( I got this info from the first thread made about this if you want to double check)

Does the beta have a defined end date?  I haven't seen one.

Received a bubble pack from MS yesterday containing a sleeveless green game case with a letter outlining the update and the Xbox Preview disc.

Functionally, I'm not noticing anything different which is good.

All reports seem to indicate this is strictly a rewritten security measure with an added bonus of an extra 1GB of disc space for developers.

According to the letter, this disc supposedly clobbers Xbox 360s that aren't registered for the Live Update program. I'm actually kind of tempted to see what happens.

It will cut an unregistered console off of live until the beta is an official release.  I've seen a couple of posts where it happened to people. 

Has anyone who was in the BETA gotten the released update yet?  I got an email saying they had finished all of the roll outs, but I haven't gotten anything yet.