Great game, but not there's not enough to do for it to be worth $60.
Now, I've only played Firefight once, by myself, but even though I was alone, it was still quite fun to play and I can definitely see myself playing Firefight with my friends in the future, and I'll be Sgt. Johnson to boot, which is the nice perk you get for pre-ordering ODST at Gamestop or other stores involved in this offer.
One thing I don't quite understand is why they shipped that Halo 3 Complete Multiplayer experience disc. Most people already have all the maps other than the new ones so they might as well have just shipped a redeem code for the new maps. Oh well, I guess it's to make it look like it is actually worth $60.
So, in conclusion, Halo 3: ODST is a great game, but it's missing something for it to be on the same level as Halo 3.