Well I have now returned from Japan the proud new owner of............ Nothing.
Couldn't make up my mind. God damn it!
I am so tempted by the 5d3 that it has prevented me buying anything. I need to get my hands on one, probably by renting one, to see if I can live with the reach loss.
Will keep post updated if I can get my finger out of my butt and take action

You are not alone ! After reading this and similar topics, I started to think about 5DM3, instead of 100-400ii and 7Dii.
I am still not sure how it will visibly improve IQ though. There are lots of high enough quality 7D pictures around, super sharp bir pictures etc.
If someone is willing to explain or show samples I am really interested in following the post.
Do
I will keep my existing 7D for wildlife and use 5DM3 for portraits, home studio and street photography. Full frame pictures are always shining !
But wait, can't 7DM2 do the same thing at "fairly" high quality?
Loop

but the quality is without a doubt like using a prime. Other 3rd party zooms are very good but the micro contrast of the canon mk2 zoom still trumps them in overall image quality and AF accuracy. 
