I have been playing the Arad2 Tank map in the T34 lately and having tons of fun.
My point, most times I am able to get a kill on the PzIV with 1 to 3 shots. In fact this morning I was able to get 3 kills in a row with 1 shot each in about a minute. The more I play, the less invincible the PzIV seems to be as a lot of others are claiming.