Also worth noting is that at the time of the M4’s introduction to the Eighth Army in North Africa, it was a very competitive platform.
Some applique armor and a 17 Pounder (as in the Firefly) and you have a pretty decent tank. The Israelis ran their M-51s almost into the Eighties, IIRC.
Did you know that if you take into account the slope angle the M4 Sherman Jumbo (E2) had almost as much frontal armor as the Tiger?