I have much experience with Vista and used it for a long while. While I love Vista as an OS and I like the interface, I still choose to use XP for various reasons. XP is much faster on about any machine today than is Vista. It also runs games flawlessly which Vista does not. What prompted me to go back to XP initially was the inability to get Half Life 2 Episode 2 to work correctly on Vista.
For those who mention cutting backwards compatability, thats exactly what MS should NOT do. The biggest problem with Vista in the eyes of the average consumer is that even it does not have enough backwards compatability. Believe it or not, many businesses are still running programs from the MS-DOS era and Vista just does not work for them. What really needs to be done though is a transition from 32-bit to 64-bit. Its appalling that pretty much all retail PCs today carry the 32-bit version of Vista. I understand having a 32-bit version for those with older computers, but the 64-bit should be the main and marketted version. Last I read, intent was to keep Windows 7 as 32-bit as well, which I dont see happening as average RAM will be above the 3.2GB barrier by the time the Vista era ends. Also, the Home and Pro versions of XP worked real well....we don't need 6 different versions.
As for me, I look forward to a time when I can use Vista and get the same productivity as I get on XP. OS upgrades should provide greater functionality, not take it away.