Well sorry to disappoint, but in the flesh he is wholly unimpressive. He's skinny with spindly legs and there was a collective intake of disappointed breath when he appeared.
But, I do like him generally.
I do think, however, he is vastly ovverated as an actor.
He is a performer rather than an actor who inhabits his character.
Too many tics and quirks for my liking to be truly believable. And he simply tries to too hard to be crazeeee.
When he is up against a good actor he is easily overshadowed:
a teenage leonardo di caprio upstaged him in Gilber Grape, the British character actors in Sleepy Hollow outacted him, Brando and Dunaway do the same in Don Juan, Benicio Del Toro in Fear and loathing, Kate Winslett in Neverland etc etc.
He shines when he can be over the top as in Edward ScissorhanRAB and the Pirates films.
In Sweeney Todd, I personally think he is outshone by Helena Bonham Carter. He can't (imo) convey the anguish of Todd and just looks constipated instead.