I know, prolly stupid, so talk me out of it -- or into it
Seriously, I do like lenses with mojo and this one seems to have some. Not certain how often I would shoot it wide open though even though I like the look. I rarely used my Leica Luxes (f1.4 max aperture Leica M lenses) wide open, but preferred the way they rendered generally at other working apertures over the Crons (f2.0 max aperture Leica M lenses), even though in many cases the Crons were technically superior lenses at those working apertures. Conversely I do use my Nikkor 50/1.2 and 85/1.4 wide open a lot of the time.
Obvious negs: Slow AF, relatively large, heavy, and expensive. I've also read only idiots buy it for day to day imaging
Pluses are: Supposedly it rocks wide open and is so good it is still sought after for astral imaging.
Alternative is the 28/1.8G at 1/3rd the cost, but I wouldn't bother since I have the 17-35/2.8 and am very happy with it for most of my wide walk-around needs.