In "Romeo and Juliet" Act 1 Scene 1-4, what are the differences between Benvolio and Mercutio?

The reader can definitely see differences between Benvolio and Mercutio in their behavior in Act 1, scenes 1 – 4 of “Romeo and Juliet”.  First, Benvolio seems to be more of a pacifist than Mercutio; in scene 1, Benvolio does not want to fight Tyblat and the Capulets but is given no choice.  If put in the same position, Mercutio would have probably began the brawl instead of letting Tyblat start it.  Benvolio also seems to be a good listener and a caring friend to Romeo.  At the end of scene 1 and during scene 2, Benvolio listens to Romeo’s problem and even offers a solution – that they sould go to the Capulet’s party so that Romeo will forget about Rosaline and find a girl who is better for him.  Mercutio is introduced in scene 4 and from the very beginning we can tell that he is more concerned with himself than with Romeo and his problems.  The best example of this is when Romeo tells Mercutio that he “…dreamt a dream…”.  Mercutio basically responds to Romeo by telling him that he does not really want to hear about the dream because he knows exactly what he is going to tell him – this response by Mercutio is his “Quenn Mab” speech.