A lot of arguing about the T-34, people need to remember there wasn't just one T-34 though, there were several types of hugely varying conditions. Not only the M1940 / M1941 / M1942 / M1943, but their production limitations. The T-34's sloped armour was very difficult to penetrate with most of Germany's Anti-Tank weaponry.
Early T-34's had design kinks that were still being worked out, and huge numbers of them were lost to mechanical failures. During the height of Barbarossa, Tanks were being rushed out of the factories without optics, trained crews, or radios. In 1942 Tiger Tanks and Panzer IV's with extra armour and KwK 40's became commonplace, destroying the T-34 with ease. This is what tainted it's reputation.
If you got a good one (not rushed) with a good crew (fully trained) before 1942, it was a real terror, and difficult to stop. At the time of its inception, it was the greatest tank in the world. Unfortunately for the Soviets, the pressure they were forced to work under prevented it from making a very big difference before Germany was able to catch up.
