An interesting, pessimistic assessment of the two component parts of ISIS from The Soufan Group:http://soufangroup.com/tsg-intelbrie...islamic-state/

IS is now a chimera of Ba’athist and takfiri ideologies, with the organizational skills of the former helping channel the motivational fervor of the latter. The result is an extremist group unlike any other. It’s the merging of Usama bin Laden and Saddam Hussein, with the strengths of one helping negate the weaknesses of the other.