Savage fails to point out that whereas Judaism and Christianity are progressive revelations, where God reveals himself in the travails of his Elect, Islam remains in the mode of Joshua, the prophet and general. Allah is a despot; Christ is a servant. Allah is merciful and compassionate, but only to those who submit. But he does not enter covenant with his people, he does not suffer for them. Christ is the first-born; he leads from the front and places himself in peril. Allah stands beyond the horizon.
As the two religions share the same template (holy books, one god, prophets and war on heretics), I think it is important to ask the reasons for the similarities.