I teach business computer courses and computer science course at the high-school level and I tend to be the person that all the students and staff members come to when they're having trouble with their computers. I've come across so many cases of students and staff running into trouble with incompatible drivers since Vista's release. That's basically it though. Unless its something critical, then they just have to wait for the hardware companies to make the drivers available or revert back to XP. Very few problems with backwards compatibility with older software. The only person I've encountered that really had to no choice but to go back to XP was a student who constructed an XP-based HTPC to act as a personal video recorder. He had 2 identical PVR cards installed so he could watch TV while recording a show at the same time onto the hard drive. Either Vista or the Vista drivers just would play nice and he could not get both PVR cards to work at the same time. I couldn't figure it out either. So he reverted back to XP.
From my observations, the deal-breaker for Vista for most people is not the lack of support, its the price. The price for this operating system is absolutely ridiculous. $300+USD fo the Ultimate Edition?. No wonder piracy is so rampant. MacOS X costs $99 CDN at most retailers in my area and Linux, of course, is free. Also, MacOS X and Linux do not demand such high hardware specifications. I just installed MacOS X on a Mac Cube for a friend last week. The computer is probably around 10 years old but it runs like a top with MacOS X. Linux will run on basically anything.
Most of my students like the new eye-candy in the UI and want Vista for that very reason. Few realize how slow their computers will get with all the bells-and-whistles turned on, especially if they have older hardware.
When it comes to the UI eye-candy, Vista is way behind the MacOS and Linux. I run dual-boot WindowsXP/Ubuntu Linux (7.04 Feisty Fawn) on my desktop, which is a relatively fast system. I run Ubuntu Linux on my 3 year-old laptop that was designed as stripped-down, ultra-light. With XGL/Compiz on my laptop, I can really razzle-dazzle my students with the UI eye-candy even with basic IBM on-board 3D graphics. The slow-down with the eye-candy turned on is noticeable on my laptop but just barely since the video card handles most it. Linux with XGL/Compiz turned on actually runs faster than WindowsXP on the laptop. Does the XGL eye-candy on my laptop look cooler than Vista? My students definitely think so and a few of them have converted to Linux as a result. Whenever, I take out my laptop, I always get the inevitable request: "Mr. Semedo, please show us the cube again." I can't even run Vista on my laptop, yet I have cooler eye-candy with Linux. I think that's awesome. I got XGL/Beryl set up on my desktop and with my NVidia 7800GT. Beryl requires a hotter ATI or NVidia card than Compiz but the results are spectacular. The eye-candy with Beryl is absolutely breathtaking and even more capable than Quartz on the Mac.
To tell you the truth, I only run WindowsXP for Photoshop CS2 and for gaming. I also need Internet Exploder and Active-X for accessing my email from work but that's not critical. If Photoshop ever became available for Linux (even if it wasn't free), I'd be such a happy camper. My next desktop system will more than likely be a Mac so I can be Micro$oft free for the most part. For gaming, my recently purchased PS3 (my first console system since the Sega Genesis) is keeping me more than satisfied. (I can also run Linux on the PS3 if I wanted to).
