.... Regarding AF, this is in line with separate Olympus claims that this new lens can focus "25% faster than the ED 300mm Pro" which I read a few weeks ago.
@Box Brownie,
you're not doing a very good job of advising me to be Captain Sensible and not buy this lens.
Everytime I shoot on my ED 100-400mm+1.4x, which is every day (over 500 images yesterday and about 30 today) I imagine what the 150-400mm+1.25x would be offering me as an advantage by comparison. I am still enjoying my 100-400mm though.
No camera or lens is perfect but you really have to admire Olympus for their efforts to innovate. It's in their genes and history and I don't see that changing adversely in the new ownership structure.