I love love love S&G and was really moved when I saw them in concert lastyear or whenever that was... I agree that Paul was the driving fore behind the duo, wrote most (but not all!) of the good songs and was certianly more musical... But something about the way the two of their voices blend gives me goosebumps.
Also, I find their lyrics to be often beautiful and poetic without being cheesy or trite. The boys could take some pointers in that category. (Although they are getting better...)