For a small subset of people who are all on Apple with their friends all on Apple in some regions of the USA it will work great though.
EDIT: For the down-voters I would just say I actually had a macbook for a few years. iChat is technologically impressive but has near zero value when you can't connect with people. Apple promised to make it widely inter-operative and failed to do so when I was using it. They almost had to be forced to give back contributions to Webkit and open it up fully. They run a closed ship more or less in everything they do, the Apple way or the highway. This voice feature is a thin UI on top of cloud services and interoperability, both of which areas where Google is light-years ahead of Apple (not to mention they have their own social network). Android is already crushing them in sales and Apple virtually doesn't exist outside the West + Japan, tens of millions of upper middle class Indians and Chinese will be using Android eventually. Apple doesn't stand a chance in the long run, which is why they are already resorting to patent suits against superior tablets like the galaxy. It's not a BMW vs a budget car, because 1s and 0s are free the budget car has the luxury seats and trimmings at no extra cost. They are toast.