I've had Vista on my notebook from Beta through RC1. Honestly, I don't think I'll be upgrading soon. The security feature that makes it hard to hack also makes some programs flaky. Also, whenever I delete a folder with images in it, it gives me an access denied message and I have to go into that folder, delete the images, and then I can delete the folders.
The best thing about it is the explorer. Other than that I just don't feel a need to upgrade and I usually like new technology.
Re: Macs. Bah! If Microsoft did what Apple did with OS X there would be blood in the streets. Many mainstream apps wouldn't work in OS X. The solution? Have to get the new version. Part of the reason Windows has the challenges it does is because it's not just for proprietary hardware, a limited userbase, and much fewer applications. It also doesn't force programs to upgrade to work on it. Say what you want about Windows Vista but Apple doesn't impress me with its approach to things.