Took the mini 9 on a trip to Europe (instead of my 12" iBook G4). After testing a few OS choices, y decided to keep a slim and clean Windows XP and use the drivers provided on the CD (I used an external USB drive, also used to boot from).
Overall.. it was great. The weight and size are very manageable. I was able to put it in my messenger-style bag no problem. Going through security at the various airports was much easier as well. One hand was all it took to move it around. I was able to open it to a comfortable angle and place it on the tray in front of me...
The screen is bright and vivid, although glossy. I used mplayer and had no problems playing my media off a mounted SD card. Battery life was about 4+ hours. The power adaptor is light and small. Plus, it has no keyed polarity so a simple US/EU adapter did the trick. It self regulated the voltage and did not get too hot.
They keyboard... it's one of the largest in the category, and I did well typing at nearly normal speeds. Although with more mistakes due to the relocation of a few keys. Which brings me to one of my major issues with it... the key (pipe) is moved under a Fn key combination and quotes are down by the spacebar. Important for programmers and UNIX shell users.
The audio was just OK off the built in speakers, and the microphone did great with Skype. I tried the integrated webcam as well, picture was good but seems it used too much bandwidth or cpu/ram. Not sure, but I had to turn it off. WiFi was adequate, I was able to easily connect to networks. Wired access was even easier.
A very good buy for the price. I recommend it (or wait for the rumored mini 10).