70-200mm f2.8 IS + TC 2X MKIII vs. 100-400mm

Well, I have both 70-200mm 2.8 IS version 1 and 100mm-400mm. I also have a 1.4X TC II and I suppose I can test them out.

But how does TC 2X MKIII on 70-200mm f2.8IS compares to raw 100-400m?

IQ and AF wise.

I'm thinking of getting rid of 100-400mm.

a quick search would help...i recall quite a few such posts in the recent past. while it hasn't quite been at the done-to-death level, there's more than enough there to help.