Colour rendering from different manufacturers glass is definitely a curve ball - and over time some manufacturers glass changes in rendering as well (ie Fuji X series glass, the original 3 lenses are very different to later lenses).
I took the descision some time ago, to simplfy my workflow and beacsue I wanted consistency, and this meant using lenses from one supplier, I take my hat of to those people who manage to sucessfully mix and match lenses from camera manufacturer and a mixture of 3rd party lenses. Its not for me!
If I was
@snerkler I would be more worried about colour rendering across my arsenal of lenses than cost v sharpness debates. Honestly if you stare at a print, do you ever say its not quite sharp enough in the top left corner, if you do then there must be something else wrong with the image as its not catching you attention in the way the photographer intended!