User blog comment:James12708/Reapers VS. Forerunners VS. Angels from Darksiders VS. Humanity from Halo VS. Council and humanity from Mass Effect VS. Imperium of Man/@comment-4967682-20130116065115/@comment-70.197.128.185-20130116154855

Not even close. See the average UNSC ship is armed with a MAC that hits with 64 kilotons. Now while this gives even UNSC frigates better damage per shot than Council dreadnoughts, UNSC ships have several very easily exploited disadvantages:

Low range. The velocity of a MAC is 30 km/s ('cept for Super MACs). At the ranges most ME battles take place, they'd have minutes to get out of the way. Frigates could even dodge that at knife fight ranges. The UNSC, on the other hand, would have no chance of dodging 4025 km/s projectiles.

Reload times. MACs have a recharge time of several minutes (see Halopedia, Halo wiki, Fall Of Reach). Council ships fire every 2 or 5 seconds. The minute the UNSC fires its first volley they'd be sitting ducks and be quickly destroyed. This was a major disadvantage against the Covenant and those weaknesses would be even more apparent here.

Lack of shields. Albeit only on pre-4 models.

Paper armor. A single Archer could disable most UNSC ships. A single MAC could disable the most heavily armored UNSC ship.

Numbers. Pure numbers. Humanity in Halo had a population of 39 billion prior to the Covenant invasion, according to Halsey's journal while, according to the salarian councilor in the first game, plus common sense since they've had an interstellar empire since humanity's dark ages at the very least, the population of Council Space is in the trillions. If the turians are anywhere near insanely militarized as they say they are, then they outnumber the UNSC by the same proportion that the Imperium outnumbers the Council.

Pre-4, the Council can easily curbstomp the UNSC without even using 10% of their power. By 4, it will take effort, but the UNSC are low on ships and there's nothing stopping the Council from zerg rushing them to death.

As for Reapers vs Covenant: Covenant ships are, in many ways, overpowered by ME standards. They're very large and durable (a single battlecruiser takes three MAC rounds just to drop the shields) and heavily armed. They're also extremely numerous. However, they're utterly outnumbered by the Reapers. Assume that the Leviathan of Dis was the absolute oldest Reaper, even though there's no evidence of that. That would mean that the Reapers are a billion years old. Since they harvest one species for a capital Reaper and around a dozen species for Destroyers every 50,000 years, this would mean there are... 20,000 capital Reapers and over 200,000 Destroyers. Just for context, the Covenant Navy has under 10,000 ships in all. On top of that, while the Covenant have weaponry that can cut right through Reapers, the same is true vice versa: a Reaper main gun hits with the force of 450 kilotons of TNT and fires every five seconds. Given that the 3 shots from a MAC = 192 kilotons (and this isn't even factoring in heat damage), then the majority of Covenant ships would be killed in one hit. The only one that I can see surviving a single hit is the ridiculous Supercarrier, but those weren't common. So when both fleets have ships that can kill each other in a few hits, the more numerous side wins. They also have a plethora of other advantages that would be insanely useful in war, including lacking a need for sleep, food, ammo, power, or water.

And this is before factoring in the Reaper's various automatic "I win" buttons. Building solar system destroying super weapons. Relativistic kill vehicles. Indoctrinating Covenant leaders. Et cetera.