i would say Spartan ops is the best place for exp. and thats not counting double exp. this whole day ive been playing (and a little last night when i got the game) and im already 21, and only recently imputed my double exp codes in. its not that hard to level up in this game. --- I walk alone in the universe as the last of The Time Lords!
SR 44, with 19 games of double xp used. The monthly challenge really made today a quick one before the cap set in. --- Dont bother screaming, dont bother crying, ignore all hope of mercy. Oh my God, they're everywhere.