I think you've described the superposition of characteristics of this lens.
unique character with atmospheric rendering or soft/blurry/vignettey
@$350 its a fun superspeed lens
I've found again and again anything faster than f1.4 is not worth the trouble.
Soft, vignette, terrible CA, focus shift, not flat field, weird bokeh, huge, heavy, expensive.
So for the occasion you want to shoot in the absence of light its an entertaining toy.
I'm contemplating building a parallel stable of "character" primes and "performance" primes.
The VC 40/1.2 recently released caught my eye, but @ 3x the price of this lens.. some of the bokeh/CA/etc did raise some concern.