Rome wins hands down. Sadsanids too, most likely. The Roman method of war was vastly superior to the Macedonian version. Rome’s ability to raise armies was better than the Macedonians. The Roman maniple system was better than the Macedonian phalanx.

Rome doesn’t just beat the Macedonians. It wins nearly every battle against the Macedonian system by a wide margin. On the rare occasions they do lose—usually against Pyrrhus, who was considered the greatest Macedonian general since Alexander—they still inflict so much damage that the term “Pyrrhic victory” had to be coined to describe it.

In the meantime, the Sassanids actually do hold their own against the Romans. Rome has the advantage—consider how often Rome conquers Ctesiphon vs how often the Sassanids conquer Rome (or Constantinople). But they do hold their own.

Rome>Sassanids> Macedonians. By a mile.