I just received my CD upgrade to a recently purchased computer. You know the kind that said you will receive a VISTA upgrade when available. In any case when my CD's arrived I read the instructions for installation. I have to back up everthing (which I do anyway), create a recovery disc (which I have already done), install the latest BIOS, run the "windowsvista/upgradeadvisor (which I should not have to do if the computer came equipped ready to upgrade to VISTA, disconnect and uninstall all peripherals, including printers, scanners, cameras and USB devices. Then after running two CD's I have to upgrade VISTA and check the BIOS upgrade.
I do not recall having to do all of this during all the upgrades, beginning with the very first one, (I am old). This is alright if you are a real techy but for my home use I will just stay with XP which has been running very well lately (having fixed most of the problems).
I believe this is directed more for business IT departments. I guess someone else will have to come along, as MS did, and direct business towards home users and topple MS as they did big blue.