Had him for seminar so I can't comment on his difficulty in general but he was super engaging and I loved the class.

Lectures aggressively, almost shouting, asks you to call him Matt and challenge him if you don't understand. Bit of an unorthodox style but actually pretty friendly. Good at keeping your attention and getting info across. First 3-4 weeks was a repeat of Physics material. Then the difficulty increased quickly. Tests were quite difficult.