Hmmm...
1 - Leon & Helena: I like this campaign, but I think people see this the wrong way. The target isn't exactly a survival horror experience. The target here is an outbreak, like Raccoon. But we get the outbreak in the beginning, when there's panic and A LOT of zombies, which mingles best with the action the series was following and the amazing gameplay (I love RE6's dodge mechanics, quick shots and overall movement). I also like to see how Leon and Helena's interactions changes from cold to warm and the fact that Leon can leave Ada aside to do what's right (I hate Leon and Ada together anyway). Helena comes off kind of bland, but she's lucky enough to be voiced by Laura Bailey, or else she would be Ruff's Jill all over again. I think Helena has potential, but we probably won't see her again. Also...I'm in the minority here but...I kinda like Simmon's boss rush. Except the fly one, I like all the other forms. I don't care if it's unreal that he can transform into a T-Rex like thing, I'm too busy having fun dodging, rolling, dual wielding my handguns fighting a freaking BOW T-Rex to care. I like most of the setpieces...the university, the outbreak in the town, Lanshiang in general (I REALLY like the China setpieces in this game...all of the buildings, crampled spaces, all the details and objects laying aroud...etc) Aaaand I think Leon's Lanshiang attire is his best look in the series so far. The only downside on Leon's campaign is that stupid catacomb level.
2 - Chris & Piers: Best story, best performace in the game by Roger Craig-Smith and the best version of Chris Redfield. They needed to broke him to make old Chris an interesting character and I liked. I also liked Piers, probably the best of the new bunch and he reminded me a lot of 98 Chris. Gameplay wise is alright too. A lot of nice encounters with enemies and more chance for me to roll, slide, quickshot and have fun. The snake boss is also an amazing segment. I just think Leon's campaign has more variety in its setpieces and overall encounter with enemies. Also, Chris's chapters tend to drag a little sometimes. The downside of Chris campaign for me is mostly Carla's helicarrier. It's a boring setpiece.
3 - Sherry & Jake: I think Jake is a worst character than Helena. Also, I think Sherry was very, very well characterized. It's cool to see a character you met as a kid turning into a badass agent (alright, she was the damnsel in distress sometimes, but in the player's hands, she's a total badass and I play her more than I play Jake). The problem with this campaign is...kinda boring sometimes? It spaces so much. I mean, RE6 is an action game, is made for action, and sometimes this campaign don't give you anything besides walking and some poorly implemented stealthy segments. I think Ustanak had potential, but he came off sort of...meh. Plus, this campaign has the two worst segments of the whole game: the snowmobile and the bike segments. Awful. RE6 was generally awful with its driving segments.
4 - Ada. Jeez, how I hate Ada in this game. Her overall portrayal and personality is so condescending. Ada in RE6 reminds me a lot of Alice from the Paul Anderson movies. And generally speaking, her gameplay was not as fun as the other campaigns. The mandatory stealth sections on the submarine and the helicarrier are awful. There are bits and pieces that I enjoy, like the fight against the ubistvo, but eh...they a had a chance to develop Ada, to give her more of what we always get with her, but she entered and exited the game the same way, just more annoying. They could've make her show anger towards Simmons or Carla, or have her show frustration...anything. But she's always smug and condescending, like Alice. Anyway, worst campaign.
Still, RE6 is my guilty pleasure and I'm never afraid of compliment his strenghts and the overall fun I have when I play the game. (or which I perceive to be its strenghts).