I'd like to add my experience with this lens which I purchased about 6 weeks ago. I have been very happy with it. It is my first WR lens and it is nice being able to take pictures in the rain - no problem! Here is my first attempt:
Attachment 130173
I also purchased this lens to have something between my Tamron 17-50 and my 55-300 when with my family. I always seemed to want to be to be a little wider or longer depending on the lens; the 18-135 fits perfectly the role perfectly without changing lenses.
For me though, it's real forte is its fast and almost silent focusing with my K-5. My family runs out of patience rather quickly, and is not always delighted to be photographed, so this lens keeps helps keep the peace
I can get some candid shots and even get a few for myself, it seems to be a very forgiving lens in these situations.
Yes, I have other wonderful lenses with great IQ, but for I need it for, it delivers good images. Here are a few more, taken at my grandson's birthday party at the local nature center. And one rose I managed to quickly get on a "no one's stopping for you again" family walk
The ducks and rose are 50% crops.
Sharon