Compared to the Bootleg "Live in Paris" when I saw them live I think they played better, but I can't be objective, due to the fact that at their concert I was too excited and everything sounded really great!
I read some live reviews where Jonas was criticized for not having a real stage presence...well actually he's very quiet, could seem cold and detached, but I think this attitude fits with Katatonia music, and the only important thing is that he sings well, I go to concerts more to listen than to watch (moreover i don't like singers who move to much or dance...)
As far as their look is concerned, they were all dressed in black ( as usual I think). I don't know if in their everyday life they always wear black cothes, but I remember that when I saw them before the concert had started, they were dressed like "normal" guys with no particular reference to a dark/ gothic look, a part from Jonas dyed black hair (I really think blond hair was better...).