I'd argue Halo 5 is the better game. Halo 4 may have a somewhat better story but its campaign gameplay is awful and its multiplayer, while still fun because it's Halo, was several steps back from the previous games.
In my opinion, I saw the story as being okay, not the best, but alright. The gameplay was kinda like discount Halo Reach (I love Halo Reach) so I enjoyed it
spartan ops was fun cuz it was kinda like a mix between firefight and campaign the only thing that sucked about spartan ops was that they reused a lot of maps from the campaign which makes sense cuz they can only but so much on the disk so beside that spartan ops was pretty solid