100-400mm or cropping 70-200?

In reviewing some image samples on Pbase, it looks to my aging eyes like the shots taken with the 70-200 lens are of better quality than those taken with the 100-400 lens.

That said, and the fact that I own a 70-200/4 IS lens(w/T1i), might I be just as well off cropping my images over taking them with the longer tele lens and not croping them?

According to the popular Lens Comparison site, the 70-200 lens seems to have better IQ (sharpness and contrast)at nearly every similar length and aperture. Though the 100-400mm lens is not bad, it's just not as sharp.

I was thinking of selling my 70-200 to purchase the 100-400(something I would have to do to swing such a deal), but am having second thoughts.
Your opinion is important in helping me make a decision.