Summary: Pentax K3. The only con with this lens is the slow auto focus but it really doesn't matter I never had any problems with locking on focus with this lens. I have used it for concerts sport and portraits and it works like a dream.
Excerpt: I'm normally a prime shooter, but this can make me leave more of them at home. The construction is first rate, including water resistance and that intangible quality of the shot is there. It is terrific as a portrait lens, and it is long enough to catch some action shots.
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Nice Bokeh, Rugged, Strong Construction
Excerpt: I bought this lens when I bought my K-30 because it was on sale. Now I wish I would have gotten the body only because I don't use kit lenses anymore. Auto-focus is super quiet, pictures are great.
Pros: Consistent Output, Durable, Easily Interchangeable, Fast / accurate auto-focus, Rugged, Strong Construction
Excerpt: Since I've owned it for a couple of weeks only, can't really comment on the SDM durability, but for now it works fine. I haven't used other cameras with speedy lenses to compare, but for me, the AF speed is OK. Tracking AF feels kinda sluggish, though.
Pros: Accurate AF, Consistent Output, Durable, Nice Bokeh, Rugged, Strong Construction, Weather resistant