Been playing today , received my copy early. I didn't get my hammerburst code in the case so I'll be emailing them.
As for the game itself I think from what I've played so far ( multiplayer only ) it's just good. I've seen several inconsistencies already with weapons and have experienced lag in a few games.
I'm disappointed with the amount of playable characters available and it seems as if the whole customization aspect is to do with mostly purchasing things with microsoft points.
If they truly want to let the players customize their characters it's about time Gears got character creation , Halo has managed it for a long while and it works great.
I'll be starting the campaign tomorrow with my friend , my hopes aren't high but I'm sure I'll enjoy it.