WWII materiel blather
Okay SO the M4 had thinner armor and an 75 mm main gun, so it was a death trap when facing big heavy Tiger/Panther tanks
which had road wheels you couldn't fix in the field, which meant most German armor fielded late in the war was the StuG III, slightly slower, slightly better armored than an M4, but the gun's comparable and fixed forwards.
So after initial terrible losses at Coen etc the number of Tigers/Panthers dwindle leaving the Allies with a very slight advantage.