Are we discussing one to one Tank stats or their overall performance in the actual war, because the two are very different. One to one the German tanks were
generally better at least compared to American made tanks, however real life is complicated and a myriad of factors, many logistical, play into how a tank performs in war.
Crew Experience
Quality of parts
Reliability of equipment
Availability of parts (i.e. tanks break down, will you have the parts to fix it?)
Availability of fuel and ammunition and its quality
Production capability and cost (i.e. loses will happen, can they be replaced and at what cost?)
Military doctrine(how does the command expect them to be used and were thus were designed for)
Combat statics can also be misleading as they often list hard numbers and fail to take into account the complex realities of large operations (i.e. terrain, offensive, defensive, reasons behind a certain action)
Life and war are complicated, its hard to list stats and causality numbers and get a real idea for how something actually happened. Both sides fought bravely with what they had, often the outcome of a battle was out of the average soldiers hands long before the first shot is even fired.
Discover magazine discussing Shermans and German Armor with the source mostly being "Armored Thunderbolt: The U.S. Army Sherman in World War II"
German steel Quality according this book wasn't as bad as some believe