They are both formidable machines, but it looks like the Germans have incorporated armor to defend against a "top attack". While that might not help in a tank v tank fight, it is significant in that you have got to figure the Russians and Chinese are looking to duplicate the javelin anti-tank missile that's been so effective against Russian armor. So a +1 for the German tank in that area.
Two stories below, looks like the Army may be looking at a
"gasp" drone tank. While it isn't as clear in the story, it looks as if a bigger gun maybe in the works for the M1. Maybe with some sort of "active" defense against incoming fire. Hopefully they are working on a more powerful and fuel-efficient propulsion system to get some extra speed and range.
The M1A1 is still the best battle tested tank produced, but the rest of the dogs on the block appear to be getting just as big or bigger.
The KF51, also known as the “Panther,” is bristling with new technology, including a larger main gun, a digital computer backbone, and a full suite of defensive features. The Panther even has the ability to counter so-called “top-attack” munitions, like the American-made Javelin missile, that are decimating Putin’s army in Ukraine.
https://www.popularmechanics.com/military/weapons/a40277518/new-german-tank-kf51-panther/It will also incorporate an advanced 130mm gun said to deliver 50 percent more kinetic punch per round than the current Abrams gun, or an even more powerful 140mm weapon.
https://www.popularmechanics.com/military/a38107679/why-the-m1a1-abrams-is-such-a-badass-tank/
What's the point of an open door policy if inside the open door sits a closed mind?