I thought Sleeping Dogs on PC looked better than Watch_Dogs in certain areas, but certainly not in others.
I was particularly impressed by the animation of Watch_Dogs.
But Sleeping Dogs has one of the smallest worlds of any game this generation. Watch_Dogs will look as good as it does, and will most likely having an enormous open world taking advantage of all that sexy RAM.
Sleeping Dogs doesn't even look that great on PC during normal day time. It really shines at night and when it rains at night because of the lighting, which did have some next gen-ish tricks to it.
But this game looked miles ahead of every GTA-like game. The gameplay also looked surprisingly fun and possibly even fresh depending on how far they take that hacking stuff. I got a smile out of hacking that one guy's bank account, reminded me of deus ex 1.