PC Magazine published a review on Microsoft Windows Vista Service Pack 1

A little over a year after the first appearance of Vista, Service Pack 1 (SP1) is nearly ready for download. SP1 is a useful but not crucial update to the OS, and one that won't greatly affect your computing day, at least not outwardly. The bulk of the development effort has gone toward upgrading security subsystems—elements that enterprise clients find appealing but consumers and small-business users won't really notice (although they'll feel better knowing about them). The bottom line is that there's absolutely no reason not to download SP1 (which you'll receive automatically if you have AutoUpdate turned on), so it's almost a given that it will become the standard in the very near future.

Microsoft Windows Vista Service Pack 1 Review