Originally Posted by Kingfish
Being lighter(G5) they will spin faster then the G6's
more balde speed is good.
That may not necessarily be correct. A lighter blade will get to speed faster, but that's only a fraction of a minute at best anyway. The heavier blade has noticably more mass, and once you get it spinning at full rpm, it will take much more to drag it down in rpm's than the lighter one will (as in thick damp grass, or sod type grass that is very thick). Mass equals more consistant rpm on the blade compared to a lighter blade. All this is provided of course, that you machine has the engine hp to run them efficiently in the first place.