Dave I did think about the Sigma but my budget would only afford me the Non APO version. So held off after reading about it and other peoples recommendations.

The Pentax feels right when handled in use. Hard to qualify but to my hands feels consistently reassuring in the use of the zoom and focusing. There's no A setting so it's all manual but that doesn't bother me. So it's only as fast as me...
No macro but i'll get a macro lens or extension tubes at some point later. Pleased with the image quality with the usual caveats at either extreme ends of the focal range. Works very well with my GX-1L.

Was worried at first about having such a focal range in use of 120 - 300mm on my DSLR. Particularly at the low end. But that's usable. I just have to move away from subject or use my kit lens.

Image from it being used last night.
http://www.flickr.com/photos/msarge/2746308580/