From my understanding as of now, it mostly had to do with order and trade routs with Constantinople and the rest of the Byzantine Empire.
As Orest Subtelny wrote, it was a way to modernise Kievan Rus:
"Sensing that Kievan Rus' had outlived its traditional animistic, pagan religion, he began to consider more sophisticated ways for his society to express its spiritual, social, and political values. By way of analogy with modern times, his position was that of a rising third-world leader who wishes to push forward the modernization of his country and consequently must adopt one of the two leading ideologies of the world's most advanced societies - capitalism or socialism. In Volodymyr's case, the two highly evolved systems of belief that came into consideration were Christianity and Islam, the religions of the lands that Rus' had and wanted to maintain the closest commercial and political contacts. Despite the entertaining tales in the 'Chronicle of Bygone Years' about how the envoys of Rus' rejected Islam because of its prohibition against alcoholic beverages and supposedly chose Byzantine Christianity because of the awe-inspiring splendor of its religious services, it was concrete political and historical factors that guided Volodymyr's choice."^1
Subtelny also notes that due to the conflicts between Kievan Rus' and Hungary and Poland (who were both Catholic), and the relative closeness of Bulgaria and the Byzantines (who were Orthodox), and that by attaching themselves to the latter provided political gains (increased interaction with Europe, access to political and spiritual lessons in Constantinople, etc). These were benefits the Islamic world of the time were not able to offer Volodymyr.