Also, bear in mind, that's a weakened Magneto.
But remembering Chronicle, Andrew really wasn't that powerful and focusing his powers tooo much seemed to cause him pain or at least required a great effort from him or at the least was enhanced due to his rage (not really sure w/c is true tho). And his "showings" in the movie don't really match up to Hulk, Thor or IM.
He murders the 3 Dudvengers, tho (Cap, Hawkeye and BW).
It'll come down to IM, Thor and Hulk and since Magneto can't affect IM's armor in any way. I'll have to admit that he gets shot by Repulsor and dies. That is unless he's given an excess of things to manipulate.