I honestly doubt Marvel would treat him any better. It's tempting to say, " screw it! Let Marvel have him! They honestly can't be more incompetent than Warner's...!" But fact is,its a good possibility they could actually do worse than DC. I could see the scenario where Superman would get owned by Thor,Hulk, Spidey and Wolverine on a regular basis.
Besides we've already seen Marvel Comics Superman. It was MAN OF STEEL by John Byrne.