I'm the former head tech and current web designer for a national computer reseller. (We aren't huge, but 300 - 400 orders a day isn't too shabby in this market.) We almost exclusively use MSI and Biostar mainboards in our systems and barebone kits, and very rarely have RMAs even though we offer a one year warranty on them. For the price, they make very solid, stable boards. We flirted with ECS and PC Chips years back, and quickly found out that the RMA shipping costs ate away any extra profit that could be made from using them.
ASUS' high end boards are phenomenal, but lately they've been making lower end boards for the value markey (like the one I'm using now). How do you know it's a value board? You can get them for $50 - $75 instead of the $150+ you'll spend on the SLI/Crossfire, capacitor-less, fanless heatpipe awesomeness on their high end models. In terms of build quality, it's more like what you'd see in an ASRock or Biostar board, and lacks some of the enthusiast features like RAM:FSB ratio and voltage control. All in all it's not bad if you don't plan on overclocking much, and it saves you money you can spend on more RAM or a better CPU.