They will have worked the hardest on Rome, after all it is the eponymous faction. It will have democracy and politics features that Macedon won't, making for a more dynamic and interesting playthrough, and since it lasted longer it will likely be able to develop more
Its armies are the most versatile and its ability to adapt and defeat so many challenges is unrivalled
Furthermore its public buildings and works, including entertainment and hygiene, are the best, and will provide helpful buffs.
While Rome starts off a relatively unknown quality to its neighbours, Macedon is hated by the Greeks, jealously coveted by the other successor states and already in an arms race with Epirus, while having a very limited army of near-immobile spearmen and heavy cavalry. Besides, the Macedonian phalanx looks a bit crap in screenshots of Rome 2:

(click to enlarge)
Seriously go for Rome