Is he a good economist, though?

Considering his academic career, he has to be at least well regarded by academia circles. It does not of course preclude he is outright incompetent hack, but it stronly point out that he's established figure in mainstream economics.

Of course he wouldn't be first and not the last of "great economists" that run a country into the ground, but just as in case of people like balcerowicz or chicago boys, it's not because incompetence but because dogmatically following utter nonsense and being the pawn to imperialism (to be fair at this point the question of competence stops being relevant).

"The Economy" is about as hard a science as play-dough. It's all just made up bullshit.