I can't speak for the iWill board. I will say that after my experiences with Abit boards, especially the original KT7, I would have a hard time recommending them to anyone...
I do have an A7v133 board, however, and it runs great! I have it running now at 149 MHz FSB (memory unstable any higher), with no problems at all. I would still say, however, that it is not worth the upgrade from a normal KT133 board, especially not if you have to foot the entire bill. If you resell your old board in order to pay off most of the new one, like I did, then it might be worth it.
Of course, you can see I am a fan of Asus boards. I've never had any trouble with them. They are stable, reliable, and Asus has good tech support in case anything goes wrong (or the board breaks), so I stick with what works.