I really only liked halo 1 and 2.
Halo 3 was pushing it a little, was still halo...
The rest were just......so far into another type of game it just did not appeal to me.
Also; I didn't like the ending to halo 4, seriously, like, cortana is an AI, period.
I would go into more detail but would probably be spoiling it for someone else.
It was like it surpassed that realism of feeling you're actually controlling masterchief and fighting an ancient alien race and just made it a fairy tail.