Indeed. I was surprized by the "out of the box" quality of generated jpegs. Plus, the available PP tweaks are generally sufficient. The most missed thing would be the cosmetics function in LR or PS (to remove dirty sensor-originated stains).
Otherwise the Summicron is easy to work with. You can forget about distortion, and the pics are relatively aberration-free from f/2.8. (relative to Df resolving capabilities, I mean).