What makes God, as Christians view him, anymore believable than the existence of Buddha, Allah, Krishna, any other deity from any other religion?
well, i can only speak from my own experience, and i haven't ever practiced a religion other than christianity. a long time ago, i did something that i had an unreconciled feeling about, and because of that, i decided for the first time in my life that i really wanted to know the truth about god. so i told him that if he was real, then i wanted him to show me. in the meantime, i got a book on the world's major religions. it gave a very good general overview of what the religion was all about and how it was practiced and by whom. after i read it i concluded that they were all pretty much the same. not in circumstance but in behavioral outcome. i mean the truth is the truth, and in a lot of ways it's really obvious, so any particular religion can't stray too far from it and remain credible. the only one that stood out to me was christianity, because it was the only one that claimed a messiah. so it seemed to me that truth could be found within all major religions, but a saviour could only be found in one. so i thought that christianity may not be the only word, but could be the final word.
since then i've had many spiritual experiences that have confirmed that idea.