root@kindle:/# uname -a
Linux kindle 2.6.31-rt11-lab126 #1 Wed Dec 12 19:58:30 PST 2012 armv7l GNU/Linux
Works fine with Linux. I do note that Slackware had some issues historically but that is in the past AFAIK. Ubuntu Mint is painless and fun with the kindles.
Given the right love you can configure Nautilus to browse your devices guts via Wifi SSH as a "Normal" folder. Now that's service : ) Helpful if you have a few lying around.
And yes. It's a LOT faster than winwoes.