Just like the last few versions of Apple's laptop-and-desktop operating system, OS X Mountain Lion came roaring out of the gate yesterday as the best consumer operating system there is. At first glance, Mountain Lion looks like an identical twin of its predecessor, OS X Lion. Upgraders from Lion will face an almost flat learning curve, because almost every feature they've learned to use works in almost exactly the same way as before. But Mountain Lion unobtrusively...