Sleeping Dogs has more than just good graphics. Its a reasonably good story, some of the voice acting is top-notch, the hand-to-hand combat is fun, and they did a good job on the world-building. But Just Cause 2's insanity and ridiculousness cannot be matched. But yeah, if you haven't already picked up Just Cause 2 on sale for $2 or so, just wait until next time.
I havent played sleeping dogs, but JC2 is a decent game.
It has a few things that are not perfect, like mice sensitivity or vehicle drifting problems, but in general is a fun game.
One thing that Can be a bit boring in JC2 is trying to complete chaos in certain locations and not finding the last part to destroy.
The part i most loved about JC2 is the huge amount of vehicles and planes that there are.