Purchased the ASRock X58 Extreme in May 2009 and have had no issues with it whatsoever. It has been a stable and reliable board that makes it easy to OC my D0 920 to 4GHz. I leave the machine running 24/7 except for the occasional shut down to blow out the dust bunnies and/or swap out parts.
Based on recent reviews on Newegg, it seems there has been a bad batch of them, but I will tell you that if you get a good one, you will have a solid and stable mobo that just works with no hardware issues.
If/when you do buy, be sure to update to the latest BIOS and use memory from the QVL.
The joke about comparing Asus to ASRock is that ASRock is a spin-off brand of Asus...lol! And, of all the "value" brand motherboards, I believe ASRock to be the best.