A good game. Not infinitely replayable like some of the Halo titles, but remember that this is a side-story. It's not *meant* to be epic and every second of it filled with exploding alien space ninjas shooting double-bladed laser katanas out of their asses. Rambling through the city can get repetitive if you're itching for some usual Halo-fare, but the flashback missions are good (and much better played cooperatively). Yes, Dare and Buck are ugly SOBs and look out of place in a Halo game. Yes, the non-existent sexual tension is needlessly overplayed. Yes, hearing the f***ing try-hard "atmospheric" sax-fellating soundtrack while you walk through the f***ing rain in circles gets tiring. But hey, no game is perfect.
Also: The best version of Firefight mode, which was first bastardised and then euthanised in Reach by Bungie and 343 respectively. Play ODST Firefight with 3 decent friends and tell me you're not having fun.
Also Also: It comes with the ultimate Halo 3 multiplayer disc featuring ALL DLC maps. What the hell more do you want?
If you're picking up ODST these days it's likely to be a bargain-bucket purchase, so you'll be getting your money's worth.