Well, in most iterations of Christianity, God is described as triune, which is considered shirk in Islam
The Islamic god also appears to be less personal than the Jewish one (at least in orthodox conceptions), which is why he can only be known from natural signs (and not represented in pictorial form) and spoken about in parables
None of the great theistic traditions (predominantly Hinduism, Sikhism, Jainism, Islam, Judaism, and Christianity) deny that God is a person. Classical theism, as advocated by David Bentley Hart, Brian Davies, Edward Feser, and others, has it that God is infinitely more personal than we are. Being in the Thomistic tradition pure actuality, and in neo-orthodoxy wholly other, we can similarly only speak of God by analogy to beings, which by their very nature exist between Being and Nothing, between Actualia and Potentia. Theistic personalism, as advocated by William Lane Craig, Richard Swinburne, and Alvin Plantinga, turns God into a passable, contingent being - a demiurge who, if he exists, must necessarily do so only by virtue of an impassable and necessary being who is nevertheless more personal. Theistic personalism is a conception of God which arose in the last couple of centuries and is far less intellectually respectable than classical theism.