The T34 was arguably one of the most revolutionary vehicles of its time. Developed from a Christie chassis that gave them high speeds and incorporating sloped armor made it give the German's a nasty suprise when they invaded. It became the most heavily produced Russian vehicle of the war and at the time of it's introduction was superior to any enemy armor it faced as it's gun could easily destroy Panzer III's and early model Panzer IV's while their shots would deflect off it's sloped armor. It put a rush on German tanks designs like the Panther and Tiger to counter them. The T34's suffered a high casulty rate mostly due to the turret only having a two man crew which hampered the commander from focusing on the battle since he had to focus on firing. They also had to rely on flag signals and had only a small periscope to view their surroundings rather than a hatch with a 360 degree view for the commander to survey the battle. This greatly decreased tactical awareness.
This is the Russian tier III tank. It has good all around mobility, protection and firepower but like all Russian tanks can bounce a lot of shells due to their sloped design. When it is the highest tier tank it will be difficult to kill and can usually destroy several tier II tanks. Against other tier III tanks it can fight pretty even and it has a low profile making them harder to hit. Against higher tier tanks it should stick to the support role since most of them have equivalent mobility.