Once again, people are not looking at the BIG picture when comparing tanks. Stop and think about **all** the attributes of a tank before a broad stroke of the "good/better/best" paint brush is applied. There really is no such thing as the "best" tank. Sure, the Tiger is one tough nut, but it has multiple faults (painfully slow turret traverse is #1, and a slow reload time is #2, imo). The Panther will have its faults too, have no fear.
A tank can not be judged on a single merit.
The only real disadvantage the Pzr IV has vs the M4/76mm is a wee bit slower reload time and 1 less MG. Otherwise, armor, speed, main gun, and turret traverse are all similar.
The T34/76mm has the worst AP performance beyond 1000 yards (inside 1000 yards the HVAP is quite formidable) for a tank in the game (and the slowest reload at that), but yet it is fast at 35mph and well armored.
So pick your poison.
Define your mission, pick your tank, and accept responsibility for your success or failure.
EDIT: First, the M8 is not a tank. It is an armored car. The 37mm main gun is good vs soft targets only. Its speed is to be admired, but beyond that the odds are stacked against it in all ways capable vs a tank.
