"Spain to Germany"? Do you mean France?
Anyway, as a former US Army tanker for the me the big question is that of accuracy. the T-34/85 had some awesome design features.
1. It was super easy to operate, which is important when the primary operator not highly educated.
2. It was fast, which made for a difficult target to hit. And speed 'cross country' is the biggest factor in open combat
3. Sloped armor made for 'thicker' armor, which provided protection at longer rangers. Inside X yards everything is dead.
This adds up to a fast tank, hard to hit, and when hit, sloped armor provided great protection. What I suspect is the accuracy of the main gun, while a great gun was mediocre at best. I suspect the T-34 won by simply swarming German armor and killing them at shorter ranges. I've read many, many accounts of German armor killing T-34s by the dozens, beginning at 1,500 plus meters, and simply not being able to kill enough before the Commies closed in for the kill. I've never read of T-34s making kill shots at 1,500 meters. I'm guessing it happened, I've not read it.
If this is the true then the "Rule of Professionals" holds true. That is, 'amateurs talk strategy, professionals talk logistics.' If you can field tanks at a ratio of 10 to 1, and have the supply train to get them on the battlefield, you will win.
If this is true, the tank itself is inconsequential. The fact that the Soviets built tens of thousands of them won the contest. And the mystique of the T-34 is a facade. just as the Sherman won by overwhelming German armor, the T-34 did the same.
T-34, M-4 inferior to Panther, Tiger
American, Soviet production dominated German production
boo
PS Side note, I've read many places that America did not reach armor parity until they field the M-26 Pershing.