Google Now isn't designed for ICS and will not function correctly on it; which you would know if you'd actually read up on it. It uses parts of the Jelly Bean framework for the voice recognition so will not work on ICS unless the guys at XDA are able to backport the needed framework components. That's not likely to happen until the source code drops in a few weeks.
What's working so far is just a hack, so don't judge it by that. Judge it by what's running on JB.