I have both and indeed, the Prime series are definitely smoother out of the box, whereas the standard model always benefit from a regreasing and adjustment, never quite as smooth initially, though after "overhauling" and some breaking in they are quite good, never had an issue with any of them. Also,the dust cap is nicer on the Prime version. And one last thought - because they are a wide pedal, which is great mind you, if using say 175 mm crank arms ( like me ) and a lower bottom bracket watch your pedaling through corners. On my 650b converted Fuji S12S absolutely no issues - on my Rawland Stag, specifically designed for 650b I can easily strike the pedal without trying too hard. Of course, it does not help when you ride different bikes and forget but having more ground clearance never hurts!