There were no cases of M-1s being fired on by ATGMs (Anti-tank guided missiles.) No Russian Kornet missiles were found in Iraq.
The most useful weapons were the M-1s three machine-guns (a 12.7mm and 7.62mm mounted on the turret and a 7.62mm one mounted next to the 120mm gun.) The Iraqis, when they fought, waited until the M-1s were close (under a hundred meters away) and opened up with machine-guns and RPGs. In these situations, the 12.7mm (.50 caliber) machine-gun was particularly devastating, as it could tear up whatever cover the Iraqis were hiding behind. When the 120mm gun was fired, HEAT (shaped charge) or non-sabot (MPAT) shells were more often used.
The advance was so fast that the supply system could not keep up. Vital spare parts for inoperable tanks were often flown in, otherwise the tank was stripped of spare parts and abandoned. Fuel consumption was underestimated, although the army is not saying by how much. The three day halt during the extended sand storms was apparently used to bring addition fuel forward for the final push on Baghdad.
The crews, as is customary, stored a lot of their personal gear (tents, sleeping bags and the like) on the outside of the turret. In this campaign, with the frequent attacks by enemy troops armed with automatic weapons, a lot of this gear got shot up.
Overall the M-1s performed well. The crews had practiced in desert areas back in the United States and knew that a lot of maintenance was required to keep the tanks going.
In Iraq, no American M-1 tanks were destroyed outright by enemy weapons. Several were badly damaged, and some of these (the ones that could not move) were destroyed by U.S. troops to prevent advanced equipment falling into the hands of the enemy. The frontal armor of the M-1 continued to be invulnerable to any enemy weapons. But side and rear armor was vulnerable. In a friendly fire incident. An M-2 Bradleys 25mm cannon, firing depleted uranium armor piercing shells, penetrated the rear armor of an M-1 and damaged the engine. RPGs proved useless against the M-1, except in a few cases where they hit a vulnerable component (like a hydraulic line.)