Waldorf's eyes creep me out. I always liked Statler. He's more cheeky. He's really say the lines that'll make you gasp or laugh alot. Waldorf is the grumpier, Life Sucks So I'm Taking It Out On You kind of old man. But Statler has guts, I find he goes out on a limb to be funy.
It goes back to my married man theory. Statler is still spry. As the old bitter one with the wife, it's almost Waldorf's obligation to hit him and keep him in line.