Jelly Bean Android 4.1 new features:

Project Butter
This new feature has made Jelly Bean run smoother than prior Android versions. It offer buffering tweaks, and it increased the frame rates, keeping touch input events and rendering in sync better. All this together with touch prediction comes together to make things run easier and smoother.
Offline voice typing

Jelly Bean offers offline voice typing. When you have no connection or poor data connection, voice-to-text tasks is performed locally. This makes it easier to run voices against thousands of samples very quickly.
Google Now
This feature attempts to predict what you will need next and try to get it for you before you realize you need it. Meaning that your device should learn your interests and habits and try to offer you relevant traffic.
Voice search
Voice search is now supported by Knowledge Graph, which means that google will attempt to supply you with the best answer for your query.
Notifications
The notification bar can now do more than ever before. It can expand and show a part of your inbox. You can view information by opening the notifications without having to switch apps.

Is the new NExus 7 by google using jellybean or icecream sandwhich?
Have you tried the Jellybean platform? how do you find it?