I enjoy these games but each campaign has, in my opinion, been progressively worse. Excluding Reach as I thought it had a pretty good campaign, everything after the original was just out shadowed by the original. 2 was great for the initial play through, and after that it just became repetitive. 3 was so bad that I still to this day have times where I think of a part of it and go, 'Now was that in 2 or 3?' 2 and 3 are great examples that a great control layout and graphics DO NOT make a good game. Metro 2033 has some of the clunkiest, slowest controls on the planet but it is far better in my opinion.
I buy most games for the campaign single player first, and multiplayer second. This sucks as anymore games are becoming multiplayer games with a campaign tacked on(Battlefield.)
Know me by name; Shepherd of Fire!