If there ever was a tablet manufacturer that made sure its customers received timely updates, it's ASUS. Last month, the manufacturer announced that it would be updating its Transformer Pad, Prime and Pad Infinity tablets to Android 4.1.1, and on Saturday the heavy lifting had begun with the rollout of Jelly Bean to the ASUS Transformer Pad TF300. In addition to updating the OS, ASUS has added a new power saving feature, global file search, and has made "improvements to the pre-installed apps".
The OTA update can be found by going to Settings > System Firmware Update > Check Update. As for its other tablets, ASUS says that updates for the other Transformer Pad tablets will be announced "in the near future".
ASUS Transformer Pad TF300 gets updated to Jelly Bean
ASUS Transformer Pad TF300 gets Jelly Bean update, TF700 looks at watch impatiently -- Engadget
I got the Firmware update notification on my TF300 yesterday, but choose not to install it.