Folks I have this lens in Nikon mount and absolutely love it. I find my sample to be sharp across the frame at all focal lengths and at all apertures. My only negative comment is related to exposure. I find I have to open the lens up by one stop from what the meter tells me I need. I see some of your photos are under-exposed too.
I would have posted my comments on your use on the DPReview forum, however Kendall Gelner has seen fit to ban me for a week as punishment for not being a fanboy :-)