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, Sony α6000, G16 | SY14 f/2.8, Ʃ20 f/1.8, 24 f/2.8, 35 f/2, Ʃ35 f/1.4A, 50 f/1.8 I, Ʃ50 f/1.4 EX, 100L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 2.0x III, 70-300L | E-mount: SY12 f/2, 30 f/2.8 EX DN, 16-70 ZA OSS, 55-210 OSS, Metabones SB | FT-QL, AE-1P | FD(n) & FL lenses