Settling a debate need wider opinions. (My friend thinks default is good lol)
Competitively Bumper Jumper no questions asked. Being able to jump and shoot is a must.
I was inspired a while back to try out Helljumper. I had used Bumper Jumper since Reach. It took me a while to get used to it, but I learned to love it! So glad at listened to at least one thing Nooga has said. 
Default for buttons, Legacy Southpaw for sticks
I went back and forth on this swapping layouts and swapping button-mapping in the Xbox 1 settings, and I arrived on the following:
Emphasize gun-fight maneuvers and skill jump techniques without having your thumb leave the aiming/looking stick.
Greenthumb is best, but swap Left Bumper (Throw Grenade) and B (Crouch) so you can crouch in gun fights without leaving the aim stick. I think crouching is much more effective in gun fights than jumping. Crouching also is important in many skill jumps, like Fathom bottom mid to top mid. Jumps and grenades are the only things you have to leave the aim stick for. I can’t find a better set-up for a standard controller.
Bumper Jumper requires the right stick-click for zooming in, which affects your aiming, makes it more of a hassle to re-zoom, and makes stabilizing for skill jumps awkward.
Default has B as thruster pack which is not good for the middle of gun fights, requiring you to re-aim after the thrust.
I bought the $30 Strikeforce Mod pack with two paddle buttons that plug into the battery pack slot and use Green thumb with no Xbox settings button remaps, but with the two paddles as jump and crouch. I LOVE it and highly reccomend the Strikeforce Mod pack. $30 at Walmart, maybe $35 at other stores. I don’t use any mods, but I doubt the thing is legal for tournament use. A Scuf or Elite controller would cost like $150 though, so I’ll stick with the Strikeforce.
Depends on what you’re use to. Some people use helljumper lol. B jumper is nice but I hate the aim in so I stick to default. I’m not bad at the game but I’m not great either so who knows.
Am I in the minority here by using Halo 4 settings?..
Only downside is I can’t crouch in a 1v1 battle to throw the enemy off like they can. But every other setting throws me off and I can’t be bothered this late in the game getting used to a new settings so I just try strafe as quick as possible.