The Russians were the only army that had well-conceived tanks of modern concept in 1941. The Russians were handicapped by the purges of the latter 1930's that wiped out most of the senior officers who were capable. That process almost disabled the Red Army. Fortunately, there were a small cadre of capable generals, and enough good men to stop the Germans before reaching Moscow in late 1941. The Russians had early versions of the T-34, which was like a well-armoured and gunned British cruiser tank, and the KV-I heavy tank, which was armoured on the scale of the Matilda infantry tank. Both the T-34 were equipped with a rather low-velocity 76.2mm gun, but this was replaced with a longer-barreled, higher velocity 76.2mm gun that was superior to anything the Germans had in 1941. The British cruiser and infantry tanks looked poor in comparison with the Russian tanks, as did the German tanks.
The Germans had to rely upon the "88" and field artillery to stop the Russian tanks. One poorly manned T-34 or KV-I could still terrorize a German army, until they managed to disable it or knock it out. Often, the Russian tanks simply bogged down, and then could be knocked out. The need to combat the powerful Russian tanks caused the Germans to rapidly improve their tanks and anti-tank guns. The Pzkw III received spaced armour and a 50mm L/60 gun, in small numbers. The Pzkw IV eventually received a 75mm L/48 gun. That same gun was mounted as an anti-tank gun. The only problem was that the numbers were too few. The Germans also started rush development of the Tiger I with an 88mm gun to combat the KV.
The British effort looked pretty pitiful, compared to what the Russians had, and soon, the Germans had, if in small numbers. Fortunately for the British, the Americans were developing 75mm gunned tanks that would become available by the late Spring of 1942. The Grants and Lees, with their hull-mounted 75mm gun were less than ideal, but by the fall, the British had received the Sherman, with a turret-mounted 75mm gun and good mobility. The Sherman also had the minimally acceptable scale of armour to allow it to compete with what the Germans had. The Italians lagged considerably behind at this time, as the best they had, by 1942, was the M15/42 with the longer-barreled 47mm gun and somewhat better armour. The British only produced better tanks by the end of the war. The Centurion, then only in prototype, was one of the premier tanks of the post-war period.