Yeah, but Duff actually has some "singing" basslines - not that Clayton doesn't, but I was talking about stuff like the the intro to "Paradise City" and the bass part in the beginning of "Civil War" - he also did a great job complimenting the piano in "Estranged"
One thing they both have is good adhesion to the drum set - both players understand what "groove" means.
I brought the Adam Clayton thing up with some of the guys at Bass Central, and none of them had anything bad to say about his playing.
I agree with the whole "ask a drummer" comment when it comes to good bass players, esp in a rock band.