Well, they both said "angels" appeared to them. (Muhammed even thought it was a jinn -- a demon -- at first). Which resulted in extra "revelations."
And per the head of the Lds apostles in 1838 -- Thomas B. Marsh -- who swore out an affidavit re: Joseph Smith...so did Smith:
I have heard the Prophet say that he would yet tread down his enemies, and walk over their dead bodies; and if he was not let alone, he would be a second Mohammed to this generation, and that he would make it one gore of blood from the Rocky mountains to the Atlantic ocean; that like Mohammed, whose motto in treating for peace was, 'the Alcoran or the Sword.'
Source: Lds 'apostle' affidavit about Smith-as-Mohammed
When Christ tells Smith he never knew him.....