*sigh*
Lots of fail in this thread. Some of you guys need to read up on WWII armor in a big way. Stop the hear-say, stop the "ours is/was better" , and stop the wishful thinking mentality.
Armored warfare in WWII, much as it is today, has a LOT more involved than just the caliber of gun. Most people don't know that the T34/85mm was LESS effective than the US 76mm, British 17 Pdr, the Panther's 75mm, and even the Panzer Mk IV's 75mm in regards to AP ability. Bring in the 85mm HVAP and it brought it up to par under the 1200 yard mark. The only thing the Soviet 85mm did better than the other guns previously mentioned was lob a better HE round. Oh, and speaking of the T34, the earlier version with the 76mm main gun was inferior in every way to the US 75mm found on the early versions of the US M4 Sherman. Think about that.
The ultimate trump card(s) in tank warfare in WWII was range and angle of impact. Bring in the quality of optics, the reload rate, the training of the crew, comms, etc., and the discussion of "who would win in a Pershing vs Tiger I fight" becomes a lots different. BTW... the US 90mm was on par with the Panther's 75mm and Tiger's 88mm in terms of AP ability. It was LESS than the King Tiger's 88mm by a long ways.