Someone asked what it should look like (I cant fund the thread now). I got a little caught up in some self inflicted Robo3d printer issues, but here is a sample of what I think is a good example of what a cube should look like once your dialed in pretty well. Note, there is a little z-ribbing on this one, its a combination of the filament and the layer height I left at .2 instead of .2098 or whatever it is. But this shows about how sharp the corners can be (from my experience anyway). It looks perfect in person, and it is 20mm across.