So I have read Murder Machine, sins of my father, and am like 3/4 of the way through deal with the devil. I think im getting Enforcer or Casino.. Which is the better of those two? Or are they both must reads?

After that it's wide open.. I was considering Donnie Brasco, wiseguy, Five families or boss of bosses. I am mostly interesting the American mob. Anyone have any suggestions for a must read? And what is the better of the books I just mentioned. Thanks .