A good compromise lens in terms of size, weight, optical quality, hopefully durability (an unknown so far, but seems well engineered). Corners a little soft at 300mm, but expected. Corners quite soft at minimum focus distance, even stopped down, but also expected.
VC well done, and worth the upgrade if you have no IS/VR.
Unexpected issue is that the AF front-focus/back focus shifts with shooting distance. This has been reported on the net and mine suffers. The camera's focus adjust setting for distance work needs to be different than the setting for close focus. This is an issue for close-up workers using AF (but rocking back and forth is often as useful, of course).
I don't know if this is a design fault or an intermittant problem with some lenses. There is discussion on the various sites, if googled.
Colour rendition is warmer (yellower) than Canon 100-400, and Nikkor 70-300ED and 80-400.