Does anyone has both 24-105L and 70-200F4iS?

Please let me know how does the 24-105 perform against the 70-200F4IS?

Does the lens have good contrast and sharpness as the 70-200IS? I checked pbase and haven't been impressed.

I can't decided whether to upgrade from sigma 18-50mm f2.3 Ex macro to sigma 17-50ExHSM OS or the Canon 24-105L. I will need to sell my old lens to fund the new purchase and I can get the Sigma now but I would have to wait for the year end bonus for the 24-105. I am happy with the Sigma but focus is a bit slow. The only gain for going with the sigma is HSM and OS but I feel it's too short for my shootings.

Well 24-105L has good range but not that wide and and not F/2.8. If I can keep the sigma then it's not an issue but don't know yet.
thanks
tran.