Its brilliant. Story is great and its by far the best looking 360 game Ive played. Facial animations are better than anything else Ive seen.
I like how the story is going. Its so much better than Halo 2 and 3. Cant really have a full opinion until I beat it though. Gonna have to be something special to beat Halo Reach's ending.
I havent tried Spartan Ops yet.
Overall its what I expected it to be - A brilliant Halo game. I really need more time with it though to give a full opinion.