There is not one piece of hard evidence to show that the JS3 saw combat in WW2, so talking about it in terms of WW2 tanks, is useless. And yes, I do know about the tank.
The JS line of tanks, however, do suffer from the same drawbacks I stated above. The JS line was also produced in nowhere near the same numbers that the T-34 line was.
The T-34 was the main battle tank, and the JS line was used in the support role, for good reason.
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34th SS-Freiwilligen-Grenadier-Division Landstorm Nederland
"Meine Ehre heißt Treue"