The boy and I went to see Watchmen on Saturday night. I was fairly impressed with how closely it followed the graphic novel, having just finished reading that. They made some fairly stupid choices, though, such as changing Bubastis's color for no reason and blaming John for the nuclear blasts rather than banding the world against a different outside force. Although that one I could understand...
Anywho, I swore I wouldn't talk about the blue junk, but I can't resist. It wasn't really all that noticeable or distracting. Until. There was a scene near the end of the movie where he was walking towards the camera, and the realistic juggle animation was only slightly less distracting than Lori's coochie-cutting bodysuit. How'd you like to have been the guy who has to animate Dr. Manhattan's jiggling blue junk? Yikes.
As far as violence? It's an adaptation of a graphic novel, so it's what you'd expect: definitely gory, in a comic-book way. Be prepared to see some bone, some muscle, and some splatter.
I'd say, if you've read the graphic novel, fork out the cash to see it in theaters. If not, it may be a little dense for your tastes. Overall? I'd give it eight jiggling blue junks out of ten.