Mark III is one of my favorite tanks on the German side.Cheap to buy when your req.-points not enough to buy bigger guns and capable of destroying any allied tank.Armed with a 7.5 cm Kw.K(L24) or is it 5cm? Check this out, is it a mistyping on the info or the ingame data?and 2 MG 34 it is a really good buy in my opinion, relatively fast and controllable  with a pretty high rate of fire.
I could choose this tank every game, if my points are low or if I think I need a fast and reliable supporting tank to my infantry.
Weakness?...Yes, it has thin armor and therefore  is vulnerable to grenades so don't drive into  throwing range of infantry.Of course this means that it wont generally stand a direct hit from an allied tank or gun.