Em would win any battle.
He has time to sit and plot on somebody that he can study.
<< That format is made for the Eminem thinks.
He gets to the root of his opponent's psychology quicker and wittier than anybody and he's funnier than anybody. A few cheesy years of shit puns and silliness aside, when he's on-point, this is EMINEM, the pure comedic fucking genius of MMLP and he has always rapped for an audience.
Any song he's ever written has had a crowd in mind, whether it's in reaction to something or to directly cause a reaction, which sounds simple and obvious / like all do that but he more than any other rapper is obsessed with the listener's perception and how to manipulate it.
Em would write the deadliest fucking lines ever being able to study somebody and then with the threat of being humiliated in front of a crowd and his absolutely insane arsenal of dazzling delivery tricks? He would blow everybody back with his filler (through sheer execution) and KO them with his character-attack lines.
Remember when everybody thought SH would absolutely destroy him? COUGH BET CYPHER, lol.
People are dumb as fuck to evaluate Em the same way they would Jay or Nas or even Budden... as if they are in the same category or the same as him just because they're all famous. Eminem still raps as if his life depends on re-writing the fucking history of technique from scratch and people are so used to his potency that it's taken for granted, but put him in the arena with battle rap dudes who people think would easily destroy him and you'll suddenly realize again how far ahead and unique he is, to everybody.