Hi, I did try the Nikon version (as, unfortunately, my Pentax stuff is only M42 by now, but which I still enjoy). I haven't had time to use it seriously, so take my comments with a grain of salt and pepper :)
Build quality seemed excellent. Heavy, metal, good. I wouldn't fear about the lens (although I had unpleasant experience with the cheaper Tokinas, both 3.5-4.5/20-35 - awful, broke thrice before money return under guaranty; and the new cheap 2.8/28-70 ATX SV - zoom ring was tight in some spots). I took only few shots at 2.8 on digital, which were sharp enough. The specimen I tried out (it was used) had quite slow AF, though. Not small AF adjustments, but it was slow going the whole cycle. Which can be a paint when the camera's AF system misses and the lens hunts. the old Sigma (not HSM) and Nikkors (not SWM) were about noticably faster, and the new HSM/SWM/... lenses are pretty fast. But it was only a quick test, and the lens might have been a bad specimen. Manual focus was OTOH very fast, some might say loose, but I did like it. So I wonder, if there was anything wrong with that lens' AF gearings. That's not much help is it :) Fra
