The Sherman tank was comparatively fast and maneuverable, mechanically reliable, easy to manufacture and service, and produced in many special-purpose variants, whose capabilities differed greatly. It was effective in the infantry support role. The Sherman performed well against World War II Japanese tanks, Italian tanks, and the German standard tank of the time, the Panzer IV medium series. However, the typical Sherman was significantly inferior in both armor and armament to the German Tiger heavy tanks, Panther "medium" (heavy by US standards) and some of the tank destroyers fielded by the Germans in 1944.
When the US encountered German tank units containing large numbers of Panther tanks in 1944 high US losses sometimes resulted. However, Panther and Tiger-equipped units frequently suffered defeats. Shermans defeated heavier tanks by use of superior tactics, or by using upgunned Shermans working with tank destroyers such as the M36 Jackson (with a 90 mm anti-tank gun) and the M18 Hellcat (a mobile, fast tracked vehicle with the same 76 mm gun).
The majority of losses of Shermans were not from battle with other tanks, but rather from mines, aircraft, infantry anti-tank weapons and, on occasion, friendly fire. Although American tanks were less powerful than their German counterparts,US armoured forces ultimately triumphed because of numerical superiority, a more consistent supply of fuel and ammunition, and the allied air superiority (with aircraft being the biggest danger to the lines of supply for German tank units).
Nonetheless, the fact that the Sherman tank was significantly inferior to the German Panther has remained a subject of sometimes bitter controversy and recrimination to this day. Sherman crews had been told prior to Normandy that the Sherman was the best tank in the world but this was patently untrue as demonstrated during that campaign.