Been running a board for a few weeks here, works pretty well. Generates stunningly little heat, very easy to cool.

To get the BTCMiner software running under BSD, you'll need to build libusbJava (in the USB SDK) and make sure /dev/usb? and /dev/ugen? are accessible.

Have also loaded a custom bitstream (just a clock divider FF chain), to see if it works. Works okay, just remember you need Xilinx Foundation, not Webpack, to use the spartan6 lx150.