Tanks for Ukraine: American or German?

There has been a bit of discussion over whether or not to send modern heavy armor (main battle tanks) to Ukraine. Almost everybody is pointing to Germany's Leopard 2 (pictured) as the most likely candidate. But the Germans, for a variety of reasons, have thus far balked and are instead arguing the US should send some of our own heavy tanks, the M1 Abrams, first. While we are sending a lot of light and intermediate armored vehicles, the War Department has said no to the Abrams citing the tanks generally higher maintenance requirements compared to the German Leopards. For those interested, a pretty good comparison of the two tanks can be found here.