I really haven't been in a position to experiment very much with regard to comparing the IQ with other glass.
The f/l range is very convenient as a "walkabout" lens and, apart from a bit of purple fringing around dark objects silhouetted against a bright sky, it seems to perform quite well.
I'm not much of a "pixel peeper" at any time; theatre and performance photography on 1 stop pushed Fuji 1600 colour negative filmstock is not for the technical purist
but it does produce some intriguing images!
I hope that I will be able to give some attention to re-acquainting myself with my well used (and occasionally abused) M and A lenses. When/if I succeed in doing so, I'll post some conclusions.
Ciao4Nao