Because my primary photographic interest is wildlife, by far, the majority of exposures I make are with this lens. I am still finding out how good this lens is. The pictures keep getting better which tells me that the lens is not yet the limiting factor.
Could it be faster? Absolutely. Do I care? Not sure...depth of field is already pretty limited at f/6.7.
Could it be sharper? Not much.
Could it focus faster and hunt less? You betcha this is a real problem.
Bokeh varies from pretty good to borderline hideosity. Improvement needed.
It also needs a tripod collar.
I, along with other wild-lifers are anxiously awaiting the arrival of its replacement; hopefully, in September.
Will I buy it? Not at all sure...the problem is that the current lens is amazingly inexpensive, compact, weighs less than two pounds, and fits in my camera bag with the hood on (not reversed). I'll hate to give that up.
I have seen enough people in Africa struggle and miss shots with their huge, unwieldy Canon artillery that I know I'll never go for larger or heavier than the Canon EF 100-400mm.
Grey-backed FiscalSony DSLR-A700, 1/500s f/8.0 at 330.0mm iso400