Question

What made Judaism appealing to followers?

Answer 1

Well, God created the World and established Judaism soon after Adam and Eve were cast out of the Garden of Eden. It was appealing because God had a personal relationship with them. He made covenants which stated that He had plans for them. He would protect them if they only followed His laws. 

Answer 2

I believe it because they give people a sense of belonging to a certain community.
Rather than tied solely to religious aspects, Judaism followers treated each other like they're belonged to a close family (they are taught a similar culture, way of life, way to behave, etc.)
This type of sense belonging was really powerful since humans are naturally created to work as a group rather than following individualistic pattern.