DEFINITELY Halo 4. Much deeper lore BY FAR. Great and emotional campaign. Brilliant graphics on a 7 year old hardware. CGI on cutscenes is almost indistinguishable from live action. Multiplayer has a higher skillcap. Needs a lot of quick decision making and skill to be good at the game. Weapons are balanced.
I'm also not sure where you're getting at with this sticky/auto aim argument either. So far I haven't noticed/experienced anything of the such as you've described and I've been playing Halo since the original CE.
I've been playing Halo since CE came out in 2001, too. That's completely irrelevant, though, as we're talking about Halo 4 here.
If you're involved in close-range combat with someone, and one of their teammates sprints past just behind them, your reticule will track and follow the other player. It just happens, and if it's never happened to you, then you're either incredibly lucky, or there's an option to turn it off that I don't know about.
I've been killed several times because I'm in a one-on-one with someone (usually DMR-to-DMR, as that's the most common weapon pairing; BR-to-BR or DMR-to-BR are the second most common), both of our shields are nearly out, then someone else sprints past just behind him, and my reticule follows, and by the time I move my aim back over to the guy I *wanted* to shoot at, he's got his final shot off and I'm dead.
I'm not saying that this is specific to Halo 4, either. Once, in Black Ops, I died because the console auto-aim decided to track the guy who wasn't shooting at me. However, this does seem to be more prominent than it was in Halo: Reach - in Halo 4, the reticule will actually "latch" onto someone a good few inches away; in Reach, the aim-assist seemed to have a much weaker magnetic attraction to other players.
Wow people said halo4 on the cod board. This game must be pretty bad. I haven't played blops2 yet was debating if it was worth it with h4 going on but it looks like no guess I'll hold out for the next one