Summary: NONE. I own the X79Extreme 9 and the X79Extreme 6. Both boards are dead. Cons: ASrock. For the last 2 years I have sent the X79Extreme 9 motherboard back to asrock 4 times with problems, asrock have sent me back the same motherboard with the same problems.
Summary: Lots of sata ports on this mobo. I love it! I have had no issues so far, and I have had it for about a month now and nothing but greatness from this board. Overclocking is very simple to do. The "EZ OC" is literally a drop down menu and you get to choose how far you would like to OC.
Summary: the quality and workmen ship of this motherboard is out standing I had no issues with installing it and setting it up everything works great. The only CONS I have with this motherboard is it only has one PCI 2.0 x 1 on it and the sound card uses it and it don't have WIFI on it.
Summary: I did a lot of research prior to picking an X79 2011 mother board for what is only my second build and with some nervousness ordered the Asrock Extreme9 Lga2011 X79 board. Sure enough the first board I got had an issue with one of the sata ports but Amazon arranged a replacement board with no issue...
Summary: It worked for my needs of 12 SATA drives. Difficult to set up RAID, took a while again no support. But my main issue is that when you put the CPU to "SLEEP" it wakes up and the sound is off. Have to turn the computer off and back on to get sound.
Summary: Yeah - I know the x99 is now the one for most. But this board is something else. ASROCK are fantastic value considering how much kit you get for your money - Now I am talking about the extreme series in general.