I got my TF700T on Tuesday October 16, upgraded immediately to Jelly Bean using the downloaded update ROM from the Asus website. Unpacked it and a copied the ZIP file to a microSDHC card.
Inserted the card into the tablet, it recognized the update and began the install.
After the install was complete I did a Factory Reset (Three times as per most recommendations.) I then did a Cold Boot.
System is fast, smooth and runs great! Love Jelly Bean!
I'm really glad I upgraded to JB on my galaxy nexus. It's so much faster and fluent. I had to flash my whole device for it to change fatory build from samsung to google but it was worth it