True, but then again SU-76s were mostly fighting against P4s which were far more reliable and easier to repair than Panthers and Tigers (which probably broke down en route because.... Germans ^^) - that and it had a very versatile role on the battlefield.
SU-76's fought everything, StuGs, Panzer IVs, Panthers, Tigers. For Panthers it just needed to hit the side or rear to kill it. For Tigers, they have APCR and HEAT rounds to increase their chances of a kill. It was less likely, but at close range (APCR) or a good hit (HEAT) they could break through the armour and knock it out. Difference is in real life they only needed to penetrate the Tiger once for it to not become a threat. In CoH2, they need to do it 9 times, so rushing up to close range is a death sentence.