The Muslim presence among slaves both in the Caribbean and America is under-researched and deserves scholarship. There are a few good things to take away.
The one, major problem is that her own position as a somewhat fanatical Muslim clouds her ability to be objective. She overestimates the presence of Islam among slaves and in West Africa and regards native African religions as savage and primitive, along with stereotyping them all as polytheistic, which is not true. Her view of African history is of a primitive people with a crude culture who only became great and did great things after Islam showed up and civilized them. She also ignores how syncretic religion in West Africa was. Islam and native religions did mix, even though she can't bring herself to admit it, just like it did in many other places in the world. Additionally, she takes detours into religious rants about great Islam is and how native African beliefs are evil witchcraft. Because she's not Black herself, all this makes her come off racist and ignorant.