I have a two PZIV's one with metal gears and one with out. If you want to run in grass all week I'd recommend atleast metal gearboxes. Moderate to rough grass seems to get caught in the running gear and the plastic gears will slip and the tank will get stuck for moment- atleast with mine. When it gets stuck it sounds like someone trying to learn how to drive a stick shift. The one with metal gears seems to just plow thru the grass. I haven't run either with metal tracks yet but it improved the off road ability of my panzerIII. In loose sand with plastic tracks the tanks are lighter and drive faster but mine seem to throw the plastic tracks in the sand alot easier than my metal tracked tanks. As far as electronics go The only problem I've had with the PZIV's so far is one burnt out smoker. But that was my fault- I didn't bother reading the destructions. I think overall the PZIV is a pretty good tank. Hope this is somewhat helpful.