While I agree that the psychedelic bleed of colours did indeed add to the generally fraught and tense mood of the book, I also enjoyed Boland's re-colouring because I felt that it added weight to the flashback scenes - red being the colour that signifies danger, the continual inclusion of red objects only being coloured in seems to imply growing danger, to the point that the world seems to focus in full colour during the sequence that results in the panel above - almost as if the Joker's world has become more real and more focused.
I also liked the little touches - the salesman's face turns White as he dies, the Joker cries tears of blood (a more accurate effect of facial exposure to corrosive chemicals), and the retcon cameo of the Penguin in that one flashback scene. Penguin is probably Bolland's favourite villain.