I more or less finished my Kossel Mini build, and after some easy calibration steps (just following along with the think3dprint3d documentation), I am already amazed with the printing quality that I'm getting.
I was never able to get really uniform z layer heights on my Mendel Max, but for delta printers this does not seem much of a problem. A colleague helped me to make a close-up photo of a print with 0.2 mm thick layers, and as you can see the precision seems to be insane, in every direction. There also seem to be much less surface artifacts caused by vibration.
In fact, with this kind of precision it probably becomes a lot easier smooth the surfaces in post processing. After a bit more calibration to avoid ABS warping, I hope to start looking into this.