where are you seeing these differences?
ive seen minor differences in price between those cards online, maybe 30 dollars, definately not 100.
last time i checked pricegrabber the ati and the fic were both 300.
anyways, make sure you check the product details/description or whatever and make sure it runs at the clock speeds its supposed to! (for a radeon 9700 pro that would be 325(gpu) and 320(ram))
as long as the cards are clocked the same, it dosnt matter what brand you get. you may prefer one brand over another because of extensive cooling, like hercules.
the fic runs at full speed so if its cheaper where u r, get it.
Long live ATI.