The hoopla is over, Vista has been released, and now Microsoft is waiting for everyone to switch. Users are switching fairly quickly, especially those who buy new PCs. It's quite likely in a few years that the percentage of Vista users will be similar to the one that Windows XP currently holds.
And why shouldn't they? Vista looks good. The amount of time Microsoft's put into creating the Aero interface, the fancy 3D eye candy, and all the other new features makes this thing look good. Plus add on all the beta-testing, and although it does contain a few minor bugs, it's nothing serious. However, Vista has come, and not a minute too soon.
Why? This is the new OS generation. With OS X Leopard promised sometime this year, and Linux distributions constantly upgrading their features, it's becoming a similarity to the game console next-generation war. Which means that people have to switch from their current OS environment to another one. Even if you simply move to the next operating system by the same provider, it's still a big change. Vista is an especially large change with all the new features and high system requirements.
So what am I saying? Well, when XP was still the modern and dominant operating system, Microsoft had nothing (really) to worry about. It was a proven operating system, and a few minor bugs would not make people jump ship and use a Mac or Linux or something. However, with not only Windows redone, but also OS X getting a revamp, this is an even more critical time for Vista. I'm not saying that Vista's bad or anything, but a few minor bugs existing in Vista could cost Microsoft thousands of dollars, whereas a similar bug in XP would do little to impact the sales.
So Microsoft has to make Vista bug-free, or at least appear that way. Because it's unlikely that people are going to switch to an operating system that's already got known problems.