Sharpness of 70-300 vs 100-400?

This may well have been asked before, but….Is there anything on the relative sharpness of the Canon 70-300 L IS USM and 100-400? That is, at various apertures and focal lengths?

I know the 100-400 is better for wildlife for its longer reach. But I wonder if other factors like weight, size, ability for more general usage, and traditional twist zoom might mean the 70-300 is worth thinking about as an alternative?

I guess in the end the sharpness is the most important question though. Is one better than the other in this respect?