Thank you for an interesting review Dustin.
I think I can see instantly that you liked the lens, that it obviously gels well with you, from the sample photos; somehow it looks like you had fun taking those photos. Sometimes we find a lens that just clicks with us and it becomes great fun to photograph anything and everything. And I get it - this Sigma seems to have a nice rendering. It's hard to put one's finger on it but it's there. It reminds me of your review of the 70-300L; I bought a second hand copy of that lens based on your review and have loved using it. According to the testing websites it falls far short of the 70-200/2.8 and 70-200/4 but I saw in your review that it rendered fine details nicely with a gentle transition to out of focus areas and nice bokeh which made it excellent for both portraits and landscapes.
I am frankly bored by the endless chase for more sharpness. It really means so little these days as almost all lenses are sharp enough so we are at the point of diminishing returns. Differences in the way the in focus area starts and finishes, bokeh shape, colours - these things really have far more impact. In particular I notice that lenses aiming 100% for sharpness often seem to look "harsh". A good example was Sigma's 50mm lenses. I owned the classic "Sigmalux" 50/1.4 and of course bought the Art as soon as it came out. I know everyone raves about how sharp the art is wide open and it is sharper than the old one, but it lost the soft bokeh and the gentle rendering and gentle fall off of focus. The old one is the one I kept, it gives a photo very similar to the Nikon Noct combining enough sharpness to capture detail without sacrificing other areas.
So thanks again for the review, I really enjoyed all you reviews and appreciate that you don't get trapped by the technical specs but instead look at real world use and in particular discuss how the photos themselves bear the stamp of a particular lens. I already own the 24-70 L II so probably won't bother looking for another lens of that type even though I must admit the OS is tempting as this focal length is very much used when I want to travel light without various primes and a tripod etc.