I'd get the Asus board. I know it's more expensive but it's worth it. Asus and Gigabyte will both be more compatible with a wider range of RAM and GPUs than SuperMicro. Also both Asus and Gigabyte will allow for overclocking where SM won't. They'll also allow memory clock speeds that simply won't be supported by SM. Asus and Gigabyte will also have a better CPU power delivery structure and will have more effective heatsinks.And since only the Asus is available at the moment, get that Definitely worth the extra money, and is $100 cheaper than the same board for the previous gen Xeons was. And here's Gigabyte's previous board for comparison purposes. Was hoping they'd release a v3 version of it but haven't seen anything.

I agree with the e5-2630 v3 being the best choice right now. With the Asus board, you can give them a 200MHz nudge and suddenly they become e5-2640's, which cost $300 apiece more