Go for the Asus - it's the nicest board I've ever owned and I haven't seen a piece of craftsmanship this good since the IC7-G Max 2 came out. It's solidly constructed and feels unbreakable. Pair it with an XP90/C cooler from Thermalright and you'll perfectly cool down the Northbridge as well as keep a 4000 chip at a cool 40 degrees with a 92mm Silenx under full load.
The SLi is really easy to set up and the mainboard doesn't seem to mind if you swap a single PCI-E gfx card back and forth between the slots - it's a very forgiving piece of equipment. RAID is easy to set up and rock-solid though SATA does have stability issues with high overclocks when in RAID so bear that in mind.
Overclocking - well I haven't had it past 10% to burn it in so I'm not the one to ask, as I'm always in favour of brute force over selective engineering

. Go on, buy it. There isn't a better built, feature packed or quieter board out there