Billy seems a lot more urban to me, the disenchanted office worker type while Bruce pretends to be from the factory floor. There is also a jazzy, sophisticated piano ingredient to Joel's music that is totally lacking with the Boss. Springsteen's chords tend to be meat and potatoes (I'm not knocking him, he's written great songs with the set of colors available to him, I could kill for "I'm On Fire", but on Joel hits you sometimes hear a chord you don't remember ever having heard before). Of ourse it's all explained by Joel being a trained pianist while Springsteen is essentially a folk guitar strummer.