Well, it's definitely Halo. Still getting used to controls, but otherwise it's a higher resolution which may actually make me feel slower (as a Spartan). I think I actually prefer playing as an Elite which I think will be great for FFA to have a decent mix. giving the two races actual benefits over one another was a great touch.
Single Player - fun story that moves along at an exciting pace
Co-op - Great with a friend, whole new story to go through, not just mashed into single player
Gameplay mechanics of the mark and execute allow you to feel badass that you just pulled off a room clear with one move. Something not found in many games.
Fisher is the elite of elite, yet Archer and Kessel feel identical in co-op. If I have to put something, this would be it.
Been piddling my away at this game since release day trying to S-Rank it. It's a great game for those of us with an hour or so to play on weekdays. I get home, take care of the chores and am able to pop into some Deniable Ops mode and select a map I need to beat on Realistic for the achievement, and about an hour later I should have it. Being engaged and nagged to spend some quality time every night, this has allowed me to get my fix.