I would say the Soviet M4C is better than the t-34/76 naturally. It would be better to compare it to the t-34/85. I have found the m4c sherman to be a little bit more effective vs Inf than the t-34/85 AOE wise. However, I still think the t-34/85 is a much more effective tank with a smaller fuel cost.
BUT.......the M4C is a little bit faster than the t-34/85, which helps.