Advice on Borderlands 2 SP mode character

just continued the game borderlands 2 using the usual Axton character, now being only halfway on the campaign i gave a thought of having a pit stop for my character selection. so far this is my verdict and now im looking for a single class that i will carry as i will play the dlcs in the next few days and go on to the main quest and finish the main game. already have level 50 Axton, used Lv 30 Gaige.

Axton - well balanced but when i unlocked the dual turret and nuke blast he's like meh now, his reloading speed is a plus.
Gaige - i love her elemental effects skills, likely her reload electro burst skill im considering this girl to be the main quest finisher.
Siren - used once, her phase lock just don't cut it
Sal - the gunzerking is fun with the right guns, but duration is still short for me
Zero - Never used
Krieg - Never used (yet)

these 6 im looking for a winner to be finish the main quest of my game and deal with dlcs, so far, its either Gaige or Axton, definitely not Maya (not my type) now im contemplating with other characters if they are SP life enough and there wont be a point where you regret it and start with another character, heck BL 2 is one train of replayability.

To you guys, who have played and finished BL 2 in many times now and got a heck of a replay, which character is the most balanced, not overpowered yet fun character? please elaborate also and if you have good skill trees out there please share Thanks

 

I had no idea axton could have dual turrets. I'm only level 38 though I think. I'm finding the increasing difficulty rather daunting.

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yeah he has, although you will deploy the 2nd turret after the first one, and both have nuke explosion upon deployment, honestly i felt like a coward if i used Axton, but nevertheless i admire his shooting and reloading skill trees. dual turrets are in the middle skill tree i think.