I think zerg would win because of the mass numbers they have but i heard the combine have more powerful aliens in their homeworld unseen by all
To be honest with you, I think the zerg are a lot more technologically advanced than the combine. I mean, sure the combine wear some cool suits, but compared to the things the zerg do in SC2 it's pretty ridiculous.
The Combine have teleportation technology, which pretty much trumps almost anything in the SC universe. Striders are also big bad mama jammas. That said, Zerg no doubt.
