Edit: i have seen that HellJumper got a key for a crate in wich there is an iten he has made, the question now becomes, does valve always do like this?

If your item is accepted you will receive the item you created in self made quality. That means it has the Community Sparkle effect.
Addiionally you will receive a key of any crate your item is published in, aswell as possibly other update related items, e.g. piles of keys (in self made quality aswell)