I am officially a Galaxy S3 Jellybean user. I’m testing/patching/modifying/etc. Jaguar 2.0 for release! So far, it’s not too different from ICS, so the transfer isn’t too painful. I haven’t given Google Now a chance, but I warn you that enabling it will certainly decrease battery life. It runs in the background and intermittently checks location.
Stay tuned for more news from me on updates.