N7.
Come on. It's no question. Cerberus just recycles the same unit types and throws them into the fire fight to have their heads blown off by Carinfix bullets while the N7 crew are more creative in their tactics. One N7 Slayer and One N7 Paladin could probably take on a whole legion of Cerberus troops alone. And even if a squad of N7 are cornered by Cerberus they can always call for help from their alien buddies because the Alliance are friends with the Krogen, Turians the geth and all the others because Cerberus are just a whole bunch of Xenophobic Master Race bigots.
Well Mr. United States JSF (lol), I find this to be a completely inaccurate assessment. It's hard to really gauge the actual effectiveness of either N7 or Cerberus soldiers (beyond what we see in ME3, who are indoctrinated drones for the most part, and shown to be rather effective when not facing the likes of Shepard), since there really isn't any material to assert what kinds of specialties and mission capabilities they have beyond Shepard, N7 MP players, Cerberus MP players, and Kai Leng, all of whom demonstrate incredible capability. Shepard of course qualifies for both N7 and Cerberus, seeing as he was both at two points in his life. But to catch up from my digression, you just pulled all of this out of your ass.
As for the Cerberus 'xenophobic master race bigots', which is hardly true and in fact slightly inversed considering alliance soldiers themselves (Ashley and Admiral Mikhailovich comes to mind here) are known for their own rather dismissive and prejudiced attitude towards aliens. In fact, as I recall, really only Shepard ever seems to be the only person in the alliance that consistently deals with aliens in any real capacity beyond Udina, whose motivations, abilities, and ideology are at your disposal to interpret.