It's amazing how close the 70-300L comes to the 70-200 f/2.8 IS II, something I had never expected or even dreamed of until I started using it.
I remember getting flamed for questioning just how much better the 70-200 f/2.8 IS II could be after shooting with the 70-300L. Glad to see my suspicions confirmed.
The comparison holds true, however that's at comparative apertures. Obviously the 70-200 has its advantages in a certain focal length range
In any case there's reason enough for me to own both of these lenses (and a 100-400L).
5D3, 5D2, G5X, G16 | SY14/2.8, V20/3.5, 28/2.8 IS, Ʃ35/1.4, 50/1.8, 50/1.8 STM, Ʃ50/1.4 EX, 100/2.8L IS Macro, 16-35/4L IS, 24-105/4L IS, 70-200/2.8L IS II, 1.4x II, 2.0x III, T28-300 VC PZD, 70-300L IS, Ʃ150-600 OS HSM S