Why do people praise Heath Ledger's rendition of The Joker when is obvious that...?

It is nothing like Jack Nicholson's Joker! What a ridiculous thing to say. The Jack Nicholson Joker was more traditional, happy and psychotic, constantly giddy and a bit childish. The Heath Ledger Joker had a very human depressed side to it, yeah it was psychotic but the childishness was gone, the only time he was happy in the Dark Knight was when he outsmarted someone. He showed anger and misery in the dark knight, two very human emoticons. Whereas Jack Nicholson went out of his way to make the Joker seem inhuman. So Heath Ledger's Joker was nothing like the one portrayed by Jack Nicholson, and it is frankly ridiculous that you would suggest such a thing.