Halo is my comfort food. If I'm stressed, depressed, tired, or otherwise at a loss for what I want to play, Halo is it. This makes it probably the single most-played series of games for me, aided in no small part because they take fairly little time to get through.
I'm one of those weirdos who plays first-person shooters for the campaign almost exclusively, for various reasons. When I have dipped my toe into the multiplayer end of the pool, it's been with either Halo or Destiny. I love the pulpy sci-fi weirdness of it, the juxtaposition of the futuristic and the mind-bogglingly ancient, and the sense of desperate hope and heroism of the series. It's probably fair to say that it's a power fantasy in some sense, with the Master Chief being a nigh unstoppable force of almost supernatural tenacity and determination, but I like that about it. Sometimes, a power fantasy is exactly what I'm after -- hell, what I need after a rough day of whatever it is that's got me down.
I don't dislike 343 Industries' handling of the series, but I'm not as excited about it as I am about Bungie's era. I'm entertained by what's shaping up to be an AI war story, but it doesn't grab me in quite the same way as the pre-343 era of the series did. In that way, I suppose, I'm glad Bungie was able to wrap the series up before handing it off. It's slightly less weird to experience a creator transition when it's a new story in the same setting, rather than a continuation of an existing story.
Halo 5 wasn't my favorite of the lot, but I still enjoyed it. My main gripe with the story side of it was that I felt as if I was expected to know who all the characters were already. Fireteam Osiris was presented to us as if we should already know who these people are, despite only one of them (Buck) being a real returning character, another one (Locke) being seen previously solely as an element of the framing device for the Halo 2 remaster, and the other two being total unknowns unless you're familiar with the expanded universe. Which is probably my one really big gripe with 343's handling of the franchise overall, I guess: It seems like you're expected to keep up with all the ancillary stuff now to really appreciate what's going on. That stuff seemed to be extra when Bungie was running the show; now it feels practically essential.
I think my favorite stretch of the series is Halo 3, ODST, and Reach. Halo 1 and 2 are always a little hard for me to go back to because of the difficulty. Halo 1's environments are difficult for me to navigate at times, and Halo 2's enemies come in numbers too great, and are a little too bullet-sponge-y, for my tastes. Halo 4 was fine, but a little stingy with the ammo, but otherwise fine. Halo 5's campaign seemed like it was barely there, but since it was harder to die (thanks to a version of Gears of Wars "downed" mechanic), that made the campaign fly by.