Well, my Da* 16-50 arrived today and I have run the gamut of emotion from elation to dissapointment. Yes, the lens focus quietly, and a little faster than the non Da*, and looks and feels nice, but at f2.8 it is not as sharp as the Tamron. The difference, which is really noticable at %100 might make me return the lens; though I want to shoot some more photos with it, as it is a more useful focal range for me than the Tamron on a DSLR.
All these were taken on a tripod, in JPG, at ISO 100 with the 2s timer shutter release.
Pentax 28mm f2.8 Tamron 28mm f2.8 Pentax 50 f2.8 Tamron 50 f2.8
I really like the way the Da* renders the the overall image better, but sharpness is important. I am just a little disappointed right now that this copy does not equal the performance of the Tamron. I am curious if others who own both lens have done any comparisons.