Superman can also be hurt by magic and red solar power. Maybe you can pair Beast Boy with Mihoshi. Planning to pair this new Superboy with Raven? I hope so.

great story

Argh, I don't where to start when it comes to writing reviews...
I'll start with the good, I suppose.

Um, it's mostly written well, grammatically and spelling. It also seems you've got the characters' personalities right.

What I did have little problems where the repetition of words. Or sometimes there would be a lack of a word that would make the sentence incoherent.
I'm sure a careful read through would get rid of the above problems.

The biggest problem for me was the Metallo character. There was no description of what he looked like. Maybe that was intentional as this is a fan-fiction, and fans would already have an image of Metallo in their heads. But for someone who doesn't know what this character looks like(like me!), some description would've been good.
Also the personality of Superboy so far seemed very familiar... Again, maybe that was intentional, but if it wasn't, you might want to rethink what he says.
Also, one line that really got me as odd was:
'He handed Raven to Cyborg,'
Couldn't Raven stand on her own? Was she that injured? If she was in such as state, then it could've been made clearer.

But yes, overall I think this piece has quite a bit of potential. With a lot of thought and work, I'm sure it could be something good.