So far I'm liking the lens. I'm heading down to NYC to the big photo show this week, and meeting up with some other photographers, and will be doing a walk, so I expect this will give the lens a good work out. So far the focusing seems nice and accurate from what I've seen. If it can focus decently in crappy lighting situation like a hockey arena, then I expect it should do great in normal conditions. I got the macro version, as my Pentax has image stabilization built into the body, I didn't want to spend the extra for the OS version. Any reading I did, it wasn't worth it in the Pentax line because of this. For a heavy / longer FL lens, it's nicely balanced, and not to hard to hand hold, and I'm not a big guy. I'm very impressed with the focus speed of it, especially when in continuous focus mode. It goes from infinity to 5 feet in a split second, and catches focus easily.