Im gonna just assume you're referring towards the mid to late years of the second world war.
German tanks are good at great firepower? Sure, somewhat true, but the allies later compensated for that by mounting bigger guns on their tanks like the "easy 8" for the Sherman, and the Soviet T-34/85. So all are even.
American tanks on reliability? Nah, ever since they adopted the "quantity over quality" approach to Sherman manufacturing, the American tanks ended up being less reliable especially on the engines, same goes with the Reds, I am not sure about their reports on engine reliability but their welding was rushed which hurt armor reliability especially before the 85 variant. Speaking of welding, the Jagtiger heavy tank suffered from poor welding and when rounds hit the armor, the shock cracked the armor along the welding lines.
To sum up, American tank's reliability is not that good but manageable, Russian tank's reliability are improved over time but is still ok, German tank's reliability are pretty good for earlier production tanks like the Tiger but got worst towards the end of the war.
Finally, production. Nope, both Russian T-34s and American Sherman tanks are great for mass producing, the German tanks suffered greatly in this area because they were over engineered and "high quality", full mass production was impossible because many parts were required to be hand made which seriously slows down production time.
Horus Lupercal Correct me if I am wrong here, thanks.