Some differences between the two. Jesus and Mohammed both claimed he was god or a messanger of God, Buddha claimed he was a man. Jesus/ Mohamed said believe, unconditionally, or we will burn for eternity, Buddha said to not believe a word he said, prove it for yourself. Jesus taught for three years, Buddha taught for 45 years. Jesus' life was shrouded in mystery: his youth, his learning, his "end," Buddha's life is pretty well documented, after all, he was just a man. Jesus said he'd do it for you, Buddha said you have to do it yourself.
Talk about apples and oranges. Jesus taught to follow his father, which he said was him,Mohammed told to follow him or Allaha and ... well, Buddha merely asked the question: "Do you know how your mind works?" Jesus/Mohammed constantly talked about God, Buddha refused to discuss divinity.
In the end, Christianity/Islam is about god, and Buddhism is about man. Christianity/Islam is religion and Buddhism is about the science of living.