Alioune released another Ultimate Marvel vs Capcom 3 clip that I'm sure any Magneto player will appreciate as it demonstrates how you can mix-up your opponent whether they back roll or forward roll on wake-up. After knocking them down with S, use his Attraction special to pull them towards you. From here, input some well timed wave dashes to cross them up, regardless of which way they roll.
MAGUS1234 mentioned to me that Magneto is just one character who has this ability. Vergil has similar set-ups when ending a combo with Helm Breaker.
Check out the full video after the jump and leave your thoughts on these mix ups in the comments!