Most of the technical reviews of Windows Vista I've read recently focus on speeds and feeds. But does that granular approach miss the real point of owning and using a PC? Can any stopwatch-based measurement of isolated tasks performed by individual hardware and software components really measure the worth of a technology investment? I don't think so. What really matters is usability, a subject I've been thinking and writing about for nearly two decades now. But what's the best way to measure usability? The answer isn't as simple as you might think.