As far as the great majority of users are concerned, Windows Vista was the greatest flop in Microsoft history and few points of view dare to contradict this. Proof is the sleuth of computer enthusiasts that still cling to Windows XP as the familiar grounds where stability and functionality combine smoothly into one easy to use operating system. When Vista came, all it took to bring it down before even starting to rise were the driver incompatibility issues and a number of programs that could not run on anything else but XP. Its slick looks were the only ones impressing the audience, but even this was viewed as unoriginal.
The endpoint here is that very few users committed to replacing a reliable XP with the relatively unfamiliar turf of Vista, waiting for all the loose ends to be tied up in Windows 7, which, as the voices of the experts claim, is a much better dish than Vista (I strongly concur).
However, plenty of users find transitioning to a new operating system quite a pain in the neck. The planning involved for having all data in familiar locations and all software installed and ready to roll with your own settings is discouraging for many users. But there are technical solutions to overcome all the trouble and bypass the most dreaded parts of the process.
For more info
http://news.softpedia.com/news/XP-to-Windows-7-Migration-122961.shtml