Conclusions
Somewhat fittingly, Service Pack 1 very much mirrors Windows Vista itself in the way it delivers (or fails to deliver) on users' expectations. If you were looking for across-the-board system performance improvements or major new features, prepare to be disappointed. Our benchmarks suggest SP1 does significantly speed file manipulations, and we confirmed those results with our seat-of-the-pants tests while copying and deleting local files during everyday usage. However, like Vista, most of the service pack's improvements are under the hood and probably won't be immediately obvious to the average user.

Of course, those under-the-hood improvements are plenty, and they include a host of reliability and security fixes as well as a good number of changes we didn't get around to testing, such as greater power efficiency for notebook systems and support for third-party desktop search software. Where the average desktop user may not notice many changes, perhaps folks with different needs and usage patterns will. Should you switch to SP1 regardless? Unless you run one of the drivers listed on this page or have another good reason not to, it probably won't hurt. Besides, you'll probably need to upgrade eventually in order to stay fresh on the security front.

SP1 is also of interest to users who've stuck with XP and are waiting for Vista to mature before making the jump. The answer there is that Vista's maturation process has been a gradual one. Much of that process has depended on third-party developers and hardware makers, who've taken their sweet time adapting their software and releasing Vista-compatible drivers. Although I personally didn't find many faults in Vista when it came out, there's no question that third-party support has considerably improved over the past year, and that Microsoft's successive patches have taken care of many little initial problems.

If you've waited all these months to move over to Vista, don't count on SP1 to make everything magically better—the service pack is very much part of Vista's gradual maturation, and it's not a sudden step up. However, with a few exceptions (you'll want to double-check that for yourself before switching), hardware and software support in Vista isn't much of a problem anymore, and the operating system is more than stable and reliable enough for day-to-day usage. Really, now's as good a time as any to switch.

Or you could start waiting for Service Pack 2.