I've had some goods and bads with Asrock. An Asrock SiS741 board for my brother pooped after about six months or so.
My other brother's i845GV based mobo had problems holding a sync lock in the integrated video (basically the image would blink in and out, or roll sometimes). The AGP (AGI, really) slot worked fine so I whacked in a Riva TNT64 and called it a day.
The real workhorses which really raised my impression were these two:
First the ConRoe 1333-D667 i945 board, which has been a nice, solid board capable of handling all the Pentium Ds as well as all the Celerons. I have an E1200 in there right now at my dad's and it's a nice little guest machine.
Second the 4Core1600Twins-P35. VERY nice board. I leaned towards it after I read up and found overall positive reviews, plus it was about $100 when an equivalent Asus board would have been somewhere around $130 or more. I had a Pentium D 945 and later a Core 2 Duo E6600, then even a Q6600, on it and each of the CPUs worked very well.
My brother currently has that board with the Pentium D 945 and he hasn't had a problem with it.
So I wouldn't necessarily discount Asrock, especially their more recent motherboards. They seem to have ironed out the quality control issues they used to have.