Reality check:
http://www.prophetofdoom.net/
http://www.prophetofdoom.net/
I wouldn't give that guy a lot of credibility, he's a Christian heretic. A member of an obscure sect, in other words he can't get his Christian theology correct much less some other religion. His lack of knowledge of history is pretty glaring.
I prefer my refutations from authentic Catholic sources. In The Great Heresies Hilaire Belloc lays out the true history of Islam.
As it is a Christian heresy the points of commonality enumerated in Vatican II are correct. That doesn't however make the religion itself correct, no more than any other heresy.