Musharna, hands down! :) It maybe slow, but it is incredibly bulky and has high special attack to make up for it. I recommend the Calm Mind set:
Musharna @Lum Berry
Trait: Synchronize
EVs: 240 HP/252 Def/16 SpD
Bold Nature (+Def, -SpA)
-Calm Mind
-Psychic
-Shadow Ball/Signal Beam
-Moonlight
High bulk + Moonlight = PITA. Max physical bulk to deal with Sawk and Emboar. Calm Mind allows Musharna to rip teams apart. Having those special defense boosts is also a nice little bonus and makes Musharna even more bulky. Also, I'll let you in on a little secret: No one knows about Lum Berry yet. Leftovers are the standard item, but Lum Berry, imo is much better as it further helps get you in a sweep range. You can choose whether you want Shadow Ball or Signal Beam, but it depends on whether Dark-types or Psychics give you more trouble than the other.