When it comes to well-support devices, ASUS is a company that stands by its products. The TF300 was the first non-Nexus device to get Android 4.2, and the Taiwanese manufacturer followed up by bringing the updated build to the TF700 (Infinity) and MeMO Pad Smart.
Today, it's sending another small (17MB) update to the TF300 that brings a handful of improvements and bug fixes:
1. IME bugs fix
2. improve HDMI compatibility with more devices in the market
3. improve the Gmail compatibility with Splashtop
4. improve the privacy : only account owner can access any UI or settings related to external storage device
5. Other minor bugs fixed
To pull the update, head into Settings > About Device > System update. If you're the type who'd rather flash the update manually, however, it has also made the full ROM available on its site.