I have to disagree here.
The idea of Vista was a new core, not features. Because it has a new core, some bugs that were fixed in XP appeared again. But that is just minor. The problem is the same as when Windows 2000 came around. It was quickly replace with XP, because Windows 2000, no only was supposed to be the OS for both Home and Business (and not Win9x for Home, and NT for business), due to a lack of drivers, and high requirements of hardware power, only time could have made that OS work. So Windows 2000 was repackage with XP with a skin and a few tweaks.
I expect the same with Windows 7. As it was said to be released by default for 64-bit CPU's, already it using the good version of Vista to start with (if you know what I mean), and will certainly contain UI improvements, consistency between applications, usual bug/security fix. But pretty much all will be same. But 3 year later after... this makes 3 year old computer become 6 year old computer for a business, meaning it is worth changing all of them. So they will all be already 64-bit, all have at least 2GB of RAM and have a GPU that can render something. So Windows 7 would work. What I am saying is if Vista was released in 2009, it would have received with open arms. For a company, most employees don't need dual cores CPU's of even 1GB of RAM, as they just use Word, and Vista lack of new features doens't impress companies to justify the replacement of just 3 year old machines. So nothing is done, everyone stays with XP.
As for the complains on Dell. There is no definition of the complains. it could be a simple "I can't uninstall this program because I can't find Add/remove program item in the control panel" type of problems, which should be ignored. And you have real problems. Also, lack of drivers for Vista by wonderful hardware manufacture that crapped on their users. Right nVidia, ATI, Creative, HP, and more? Right. Which made Vista have a very bad reputation (unless you decided to buy the mentioned companies latest and greatest hardware with your Vista, or smart enough to know it is nor Microsoft fault.)