I just recently completed my first computer build, and I'm quite proud of it. Using an AMD Phenom and a Gigabyte board base on the 790fx chipset, I've got 2/3 of the Spider platform up and running.
Installing Windows XP went smoothly, updating took several hours due to sheer quantity. Problem is, after installation, Windows will rarely boot. It gets to the loading screen, then BSODs and reboots before I can get the error code. Strictly speaking, this may not be related to the new processor and chipset. Could be anything. No idea what the problem is, but I don't care much because I mostly use Linux.
Linux also installed smoothly. Took about a day to run through the build scripts, about a 30-50% improvement over my 4 year old Athlon 64 x2. Boots perfectly and runs perfectly, no problems with hardware configuration or anything. It's great.
I would like to get an ATI 3870 or 3850, just to see how the full Spider platform performs, but I have had issues getting ATI's drivers to work in Linux. (Actually, I still haven't managed it). Maybe the driver situation has improved, but I haven't done the research and testing yet. Right now I'm running an Nvidia 8800gt, and it performs flawlessly.
I just find it strange and wonderful that Linux has better support for some of the latest hardware than Windows, on top of already being better in almost every other respect.
Any other opinions on AMD's new platform, especially on Linux, feel free to comment!