I was never a huge fan of Halo when they were all intially released, and the only ones I played on release were 3 and Reach (mostly co-op and mp with friends who bought them). So idk if my opinion is lacking what the cool kids call "street cred," but here we go.
I got a free digital copy of MCC and Halo 5 with my One S a ways back and only within the last year played through all the campaigns. I would say the worst Bungie game is ODST, which I know some people regard highly, but I couldn't really get into. I never finished it and didn't really like being a regular human or the hub area all that much. Story wise it's interesting getting a different perspective but gameplay wise I just didn't care for it as much.
The worst 343 one is definitely 5. The only thing it has going for it it that it looks great and the performance is rock solid. Honestly one of the best looking and performing games this gen IMO. But the story, level design, and forced co-op is all ass. I wanted to like the different characters but Locke is basically just a brick in a spartan suit, and the other Spartans (except Buck) are just as bland.
The second worst Bungie game is honestly Halo CE. The first half of the game is great but then it gets way too repetitive and copy-pasted half way through. It's still a good game but the Campaign obviously suffers from the rush they were in the launch it on OG Xbox.
Halo 2, 3, Reach, and 4 I all liked and only had some minor flaws (keep in mind I'm only talking Campaigns). Halo 4 in the MCC looks like an X1 game and not a 360 game; 343 at least knows how to pull off great visuals.
I think Infinite has a 50/50 shot of being the real deal. Halo 4 had a good SP but shit MP and Halo 5 was the opposite. Here's hoping they can nail both this time. Also I wanna see Chief and Arby team up again.