there is a suprising amount of common ground when it comes to the personnel, but a great deal of dispute as to their roles and significance. there was a program recently examining the common ground between islam and christian based religions, abraham being common to both but which one of his sons, ishmael or isaac, has the greater significance is a dividing point. but i don't think the differences should be regarded as negative factors, the wider the discussion the better. from what i can see, the factor that all religions have in common is compassion for our fellow man and as a buddhist i hold that value very dear while not believing in a god at all.