The difference? ISIS is a less retarded version of HAMAS. Same goals, same stated ideology, same view toward the rest of the world (infidels to be exterminated). ISIS is smarter and more effective and can take over large swaths of land to carry out its stated aims. HAMAS has been prevented from similar behavior by the IDF.
Same groups. Different levels of power. But some on here will advocate to give HAMAS more power, so they can act like ISIS. Despite not supporting ISIS (a position they have never actually explicitly taken...I wonder why?).