Is this Karloff's best performance?

I think it is a tough call, but is this the best you've ever seen Karloff? There are plenty of other movies you could nominate: Frankenstein, Bride of Frankenstein, The Mummy, Isle of the Dead, Targets -- the list is huge. I think he really goes for it in this one though. He seemed to have a real sense of fun with the character of the Cabman, but he also seems ... competitive? Everyone he appears on the screen with he is challenging to step up to his level -- and they all do it. The film is great anyway but his performance, in my mind, really elevates it. A different character from what you normally expect to see him as but extremely entertaining.

On another note, Lugosi looks like he's pretty sick.