It's been an interesting 2 months, cutting my teeth on various rigs. I've tried a lot of cards and a lot of motherboards, here's what I've found so far:

4 card rigs - Asus Z-87C, well priced mobo that took every card in every situation, never a complaint.

6 card rigs - Gigabyte 990FXA-UD3, very well priced also, took everything I threw at it in every situation.

MSI - I'm still struggling my with MSI mobo's, even after praying to the 4 gods and sacrificing a live chicken, I couldn't get these mobo's to play ball. Dummy plugs didn't help either.

Best Heat Management - If you've got the cash, my Asus Sabertooth Mobo's sat there in the middle of the Aussie summer and said "What Heat?" Both the 990FX and Z87 coped with the sun beating down on my outdoor shed without a problem. Cards were 10% cooler with these mobo's, don't ask how because they were on risers, must have been to do with dissipation from the board itself.

I'm so happy now that is all over, I'm selling all my expensive Mobo's on eBay and I can just stick with the Gigabyte for all my rigs moving forward. Melbourne receives the Asrock H81 BTC Mobo from 18th March on-wards, so I'm sure I'll just grab that from now on, but it's nice to know of alternatives as I'm sure they will be out of stock soon like every other bit of mining equipment at the moment...

If anyone has any other findings to add to the discussion please chip in...