Get the Iwill KK266, much cheaper than either and also much better in o/c. I have an athlon 1.0ghz 266fsb retail. I can overclock it to 1.4 ghz (133*10.5) easily. Very stable even without increasing voltage. (But I know it can go even higher than that) The FSB can also be overclocked pretty high, i got it to 147mhz stable. All this using the RETAIL STOCKED Heatsink/Fan that came with my CPU!!! Temp was @ 30 deg Celcius!!! (its this low cuz its cold outside and i left my window open and took the case cover off). But during regular use, and hot days, i underclock it 1.2ghz.
So if that answers your question, GET THE IWILL KK266!!!