I notice that it is a bit smaller than the Canon 100-400, which can be and advantage. Any early comparisons out there yet on image quality?
I know the Canon 100-400 II has almost supernatural performance on a 1.4x teleconverter, which would be hard to approach. I use that as my normal setup with the 5D4. But for that price, I'm interested. When I eventually get a bigger white (probably 400 DO II), I'd consider trading down to help clear the budget, especially as this would go from my primary lens to a secondary.