My bumper is 10 years old, and has the same problems in addition to a few big scratches, and some dull spots (the previous owner left the bra on in the rain).
I've tried Quixx, TurtleWax polishing compound, Meguiar's Ultimate Compound. None of these completely got rid of any of anything. So then I tried touch up paint, which works, but is still visible.
I am probably going to get it repainted this summer. I just got a quote today of about $500 to remove the bumper and get new paint baked on.
Ultimately, I think it depends on how bad the damage is, and how perfect you want the bumper and hood to be.
