For this fight the Avengers also have Loki helping them out, The Guardians of the Galaxy, David Levinson, Thomas Whitmore (pretend he survived the second film), Patricia Whitmore, Dr. Brackish Okun, the Sphere, & Dylan Hiller to aid them, while the Harvesters are lead by the Queen from the second film. Together with Tony Stark & Dr. Okun they develop the technology provided to them by the sphere. The first round is on Earth at Area 51, second round in New York, third round in Los Angeles, fourth round in Washington DC, & the final round is on the Harvesters' home world who would win & why?

This time, the balance is different. If you're not a galactic civilization that can respond almost immediately, then you'll probably be bombed to pieces before you even know that something is coming. (And then Earth will be completely wrecked by the mothership. Then the other planets, which have a mostly measly defense system, and perhaps even the other Nine Realms, which would probably do next to nothing to a shielded Mothership, and which would be mined for sufficient fuel and resources as well.)

So, if ID4 comes, goodbye MCU...

I guess I would admit, that the Avengers would win than Harvesters (that I voted)