I love this game; the campaign and multi-player are really good.
On the other hand, the multi-player just doesn't feel like Halo anymore. It feels as if they've gone for a CoD style gameplay, and in my opinion, if I wanted a CoD gameplay style, I'd play CoD.
A lot of aspects that made Halo multi-player so unique have been removed completely; even the minor things like weapons on the map: having a huge battle over a shotgun or any other power weapon was what made Halo so damn fun.
I like Halo 4 and I like CoD, but now that Halo 4 is basically sci-fi CoD, I'm looking for another game to fill that gap. Halo's unique multi-player is what made it good, but not so much anymore.
Might be just me that feels this way, but in comparison with Halo 3 and Reach, it really doesn't feel like a Halo game.