I still think that Swann is performing at the moment, but Monty also looks excellent most of the time and is still learning and gaining confidence.
I would love to try the following team:
On spinning wickets:
Cook, Compton, Trott, KP, Bell (or Bairstow depending on Bell's form!) Root, Prior, Swann, Monty, Finn, Anderson.
On less spinning wickets I'd love to see..........
Cook, Compton, Trott, KP, Bell (or Bairstow depending on Bell's form!) Root, Prior, Swann, Meaker, Finn, Anderson
And on a greener wicket which is unlikely to take spin (even on day4/5) then I would even go as far as replacing Swann with Onions/Dearnbach or Broad if the conditions are suited to his style!
But I really can't see Broad being left out, even if his form is not great with the bat and ordinary with ball!