Donald Trump: Is his speaking style and rhetoric more like Adolf Hitler or Benito Mussolini?

Probably neither, but the messages matter than the speaking style.

I don't know about Mussolini nor indeed Stalin or Mao as speakers, but Hitler was an effective orator.

Trump is painfully obviously not a skilled public speaker at all, but he still attracts his most ardent followers, most of whom likely put their Party's ideology first anyway.

However, I see no point or fairness in such contrasts or comparisons, because as individuals their public-speaking skills will be individual.