There's something chibi about his alt mode which doesn't work for me, I don't usually dig chibi. But I do like the mold, it's just that DE's colors don't work for me, specifically the shiny black cockpit and garish orange wheels put me off. I would have bought him anyway, but at Botcon they had the inevitable repaint and it looks way better, the vehicle is blue and the cockpit is gray and the wheels silver. If there's a sale on basics tho', I'll buy him for a buck fifty or more off.
It could be any of them, honestly. I was going to list Ransack as my favorite, but I just like Dead End because he is a sleek looking little car and he is a decepticon.