Summary: I really wanted to give a more in-depth review of this lens, but after eight months, I feel that I have not taken enough pictures to cover all aspects of this lens. So, I only give some of my personal experience and observations with this lens.
Summary: I took this lens on a trip to Costa Rica and I have only a few comments to add to the very thoughtful posted by others, most of which are on target and consistent with my own limited experience with this lens (I took a few thousand shots on this trip). First, the lens performs as advertised.
Excerpt: Just upgraded from an older cheaper Minolta lens with the same zoom; the motor on the new lens is totally quiet, whereas the old one was noisy; the sharpness of the images of the new lens is much better than the old.
Summary: Sony has hit a home run with this first G lens to be introduced since Minolta withdrew from the camera market. The lens is lightweight enough that it's easy to carry - much lighter and more compact than the Sony 70-200 f2.8.
Excerpt: The lens is tack sharp and has great range. It also handles well and is very well made. Its bulky but not cumbersome.
I have mixed feelings on the AF. While it is smooth and silent it is slow and not always accurate. The SSM motor also drains the battery.