For me the first think I noticed about U2 was Bono's voice. I remeber hearing songs like with or without you and still havent found on the radio and thinking no other rock singer sings like this. His voice is extremely unique and he sings with more power and more force than any other rock singer I have heard. Also he does not have the typical rock n roll voice his voice is more like somthing you would hear on broadway. His voice stuck out before the edges sound and before anything else in their music. Therefore perhaps in a way Bono is truely the greatest musician in U2 in reguards to his voice as an instrument.