I might go with this ASRock here. http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262

It's $40 more (after rebate) than that Biostar, but it has more slots, and they appear to have better spacing too. You could run 4 or 5 cards on this mobo with an adapter/extender or two.

To run 3 cards on the Biostar you'll need an adapter, and I think a good one is about $15. So that puts the 2 boards only about $25 apart. A lot of people do use that Biostar though, so it's a proven board for mining.