I did notice that the high capacity mag had alot of play to it as it had the extended leverage aspect, it hung down and acted more like a loose aircraft landing gear. The factory 10 rounder has play inside the mag well too, there is some see-saw movement. The advantage with the Ruger 10 rounder is there is less elongated leverage to worry about, it sits flush with the stock, so it is more stable. Ten rounds is fine as I shoot one or two rounds, rest, shoot one or two rounds, etc.
I think the high capacity mag would be good idea if you were hunting lots of ground squirrels and needed the firepower.