Not bragging or anything, but I got a killimanjaro on my first MP game on Halo 4. Ok maybe bragging a little
Never gotten close to one in other games. Pretty much all downhill from there.
Legendary is super easy once you know what to do. My saves got messed up a little and I didn't get credit for completing it. Had to do 3 missions all over again, but at this point I could run through them no sweat.