Compared to the other Halo games, which in my opinion were total pieces of shit clones, this one is actually quite good.
Yes, the story and single player campaign suck as expected, but you can't really get many heartfelt moments out of walking tin cans now can you? That's is not a justifiable reason by the way, Bungie should really stop their narratives as it's just not their thing.
However, the redeeming factor of this game is multiplayer which honestly could have been a stand alone game. There's new weapons and vehicles that are balanced and fit in, the armor upgrades that add a large number of ways to kill and get things done, 15+ game types with addition of the hundreds of custom games coming (Grifball made the original 15 which made gleeful, way to go Rooster Teeth) and 30+ maps with probably more coming with DLC. This only coupled with the addition of the 'real' forge, which is so outstanding that it makes any other map builder look simple and childish.
So, If you don't have any friends to play with or hate to go into matchmaking with 'H3dsh0tma5t3rr.' Then avoid this game as it's total garbage to you but if you love multi-player then this game is so worth it.