Well, they were started as a spin off of ASUS to compete in the Foxconn esque OEM/uber-budget market but recently they have been more like ASUS' wacky experimental department.As good as it might be, asrock haven't exactly had the best reputation in the past, some were shockingly bad. In fact, it's only been with SB that I've noticed them on ocuk and started hearing good things about them.
I have owned one asrock board, and that supported DDR2 + DDR plus PCI-E plus AGP, along with a C2D or C2Q chip. Pretty impressive stuff even though it was a budget board. I thought it was very good for the money and allowed my transition from an athlon system to full 775 setup eventually
As for overclocking performance... no idea... shouldn't be that bad if it's using the same chipset as others?