What we have seen is those tanks used against forces with supposedly worst state of training and almost no heavy equipment, and it not resulting in a walkover.However, the M1 Abrams, Challenger 2, Leopard 2 and Leclerc have not been used against one another by armies with comparable levels of training and combat experience.
What does seem to be clear is that the Russian/Chinese model of greater numbers of smaller tanks relying on autoloaders does not deliver very effective tanks on a modern battlefield.