How do I fix this...

@ Axislab; after the rant I received about my inadequate prints, while I didn't appreciate the manner in which the message was delivered, you were right. They could/should be better. So I went searching for answers and roamed freely among flow rates, belt tension, temp, speed, hardware tightness and all manner of variables. I have had some success as the picture will show. I have also had a major fail and don't know why. I need help with two things: 1) the "stitch" where the circle ends meet. Cura does it worse than Slic3r, but I can't get rid of it. Do I live with it, or...? And 2) the .3 cylinder is pretty good. So is the .2. But .1 resolution fails after about 20 perfect layers or so. These prints were all done with the same filament (yes, cheap stuff but it is the same with the good stuff), at the same temp from the same slicer (Cura) with the only change being resolution and a small speed change between them - 45/35/25 mm/s respectively for .3, .2, and .1
Here's the pic. Any help is appreciated!

 

OK. Back on track though still some very minimal ribbing. Going to 8mm z screws next, but overall, vast improvement. .1 resolution