I know some folks have had both of these lenses. Optically from pictures i have seen they are both great IQ wise. Please don;t suggest anything else because 500 is in my budget right now. I would love to indulge in the 70-200 2.8 IS but i cannot at this time. Pros for the f4l: constant f4 L build Q Faster AF Internal zooming cons f4l: WHITE!!!! No IS lack of 300mm PROS 70-300 IS: 300mm good image quality IS Black Cons Push pull zoom build quality variable aperture What do you guys think, ones that have owned it.