I've printed a 2x2x2 cm test cube with Slic3r (left) and Ultimaker Cura (right) and my Prusa i3 derivative machine with tight belts. The print settings should be quite equal (0.15 mm layer height, 40 mm/s outer wall speed, default accelerations/jerks). Though the top surface of the Ultimaker Cura-cube looks much better than the Slic3r-cube,
the latter has much flatter vertical walls than the first.
The front wall of the Ultimaker Cura-cube was printed from left to right which could explain the wavy result as some kind of vibration caused by the sharp y-stop at the left front corner.
But what setting could have influenced this? Should I try to manual setting of lower accelerations in Ultimaker Cura?