Muslims did not increase in the hundred years they ruled. Abbasids accepted non
Muslims which led to a large increase in the number of Muslims around the world.
The Umayyad was more focused military expansion and wanting to conquer territories but the Abbasids focused on expansion of knowledge. Another difference is that the Umayyad Muslims were referred to as Sunni Muslims and
Abbasid Muslims are called the Shiites. Abbasid were content with the inherited empire unlike the Umayyad who were all about expansion