The German generals (and to a lesser extant Hitler) knew Russia could ramp up tank production fast and had way more soldiers then them if it turned into trench warfare or even total warfare level tank vs tank or aircraft vs aircraft fights. Largely because Germany already had to deal with the UK+America+Canada on the other front and we themselves limited in their own production ability vs the much larger Russia (regardless if the Russian industry was less advanced, it was still more advanced than the biased Germans expected the slavs to be).
The simple fact the Russian's had ANY tanks that they couldn't easily deal with, let alone not destroy at all with their own tanks, totally caught the Nazi generals off guard and slowed the whole invasion down.
The technological advantage that Russia had early on can not be downplayed. It was absolutely critical.
Had they kept Hitler's egomaniacal lust to crush Stalingrad itself at bay and instead simply encircled Stalingrad to cut off its supplies and proceed to take the Caucasus oil fields instead, the whole war could have turned differently.
At the start of the war, the Germans had nothing that could touch a T-34. Well, no they had no comparable tank; T-34s are vulnerable from the air, and the Germans had Stukas.
It's worth nothing that due to the need to churn out T-34s at a rapid pace, the quality sometimes suffered, and some T-34s were badly put together. Also, it was a very uncomfortable tank to use, and the turret of that early version was too small.
But assuming I get fully functional T-34s, I'd absolutely prefer to go to war with 5 T-34s than with 5 PzIV-Ds or PzIIIs, which was the best the Germans had at the time.