It was ok, I mean the story for the fourth game felt more like an excuse for making a fourth Halo game to me, rather than an actual addition to the series.
Legendary wasn't all that challenging either, a friend and I roflstomped the game in about 8 hours, given the fact that I haven't touched an xbox or Halo in nearly a year: this is a problem.
Don't get me wrong the campaign was fun and all, but beyond the 'hypest new levels, enemies, and WEAPONS': it felt to me like the same old thing, and whether that's good or bad is up to you I guess. Still what the forget is: "PRESS B TO KILL THE ELITE"!
I haven't played the multiplayer, and I don't plan to. Since the formula for competitive multiplayer is generally the same.