After a lot of and deliberation I recently decided to grab a sigma 100-300mm over the Pentax 60-250mm or da*300mm.
It's certainly a beast of a lens.
Only had a few hours of light to play around with it tonight, but I think I am really going to like it.
Here are a few quick shots I got off to test it out..
They have my own PP taste, so the look may not be to everyone liking but I think the lens performance comes through nevertheless
A near 100% crop (F/8 ISO400) Wide open cropped (f/4 ISO 350) Bokeh is just fine for my taste
F5.6 IS0320 F 6.3 ISO 2000 Again a very large crop (Near 100%)
F/ 8 ISO 400