score:6
The Pearl of Great Price is not a cohesive book in the same way as the Old and New Testaments, the Book of Mormon or the Doctrine and Covenants are. It serves as more of a "miscellaneous" collection: two significant elements from the unfinished Joseph Smith Translation of the Bible (the books of Moses (excerpted from the start of Genesis) and "Joseph Smith--Matthew" (towards the end of the Gospel of Matthew)), one translation of an ancient document not found in the Bible (the Book of Abraham), Joseph Smith's personal retelling of the sacred events that led up to the founding of the church (Joseph Smith--History), and a short set of simple declarations by Joseph Smith about basic LDS doctrines that has been accepted by the church as a canonical declaration of belief (the Articles of Faith.)
According to BYU's Encyclopedia of Mormonism article on the subject, it was originally published in 1851 by the president of the British Mission as a response to requests for more information about the church, and at the time it contained several other revelations which have since been moved to the Doctrine and Covenants. It was accepted by the church as an official, canonical collection of scripture in 1880.
The article doesn't mention anything about LDS offshoot sects accepting it as scripture. The Wikipedia article mentions that it is accepted by "some other Latter Day Saint denominations," but does not elaborate or provide any references on the subject.