The same as anybody else using a Spartan6-LX150.  There's nothing special about this board except for the backplane option and the fact that it costs a whole lot less than the boards sold by Digilent, etc.

I currently mine with my own HDL code -- which is not performing very well yet (!).  I have deliberately not looked at or downloaded fpgaminer's code in order to avoid being the target of accusations.

If somebody posts a bitstream for an LX150-2 with an 10Mhz clock input on pin B10 (IOSTANDARD=LVCMOS33), all other communication is over JTAG, I will be happy to try it out and post results here within a day or two.  Please include the timing report (twr) and map report (mrp).

In terms of testing the hardware itself, I have run a single "lane" of my own hashing code at 320mhz (which is the BRAM speed limit on a -3 and out-of-spec for a -2) and have run current draw tests (fill the chip with shift registers, crank up the clock speed) up to 10A using the backplane power supply.  Everything worked perfectly, no errors.

(FWIW, though, there's absolutely no hope of PAR finishing with the whole chip full of lanes at 320mhz, and I have to waste an ungodly quantity of registers on pipelining.  The point is that the power supply is stable and reliable at high clock speeds and high current draw, not that you'd actually want to do mining this way (you don't).)