So I decided to make the firmware switch from Sprinter to Marlin. Wow what a difference! Before on sprinter my circles were out of round by 1.1mm and were very jittery. With Marlin my circles are out of round by .3mm and runs smooth as butter. It also runs so much quieter.
This is a Wades Extrusion gear comparison. The one on the right was Sprinter, the one on the left Marlin. Although it may be hard to tell from the picture, the Marlin print is much more round. The rest of the print quality on this part had major improvements.
Some thoughts on Marlin.... The change over was very difficult for me. It took a few nights and hours of programming to get it to work correctly. It definitely improved quite a lot but was very frustrating. The direction are very unclear at best, and because every printer runs differently it was hard to get it configured.
I also decided to get Autodesk 123d this past weekend! Pretty cool, I like it better than sketchup but still nowhere near Solidworks (which I wish I had)