The two most prominent of these, Vaticanus, which is sole property of the Roman Catholic Church, and Sinaiticus are both known to be overwhelmed with errors. It is said that Sinaiticus has been corrected and altered by as many as ten different writers. In Vaticanus is found the evidence of very sloppy workmanship. Time and again words and whole phrases are repeated twice in succession or completely omitted. While the entire manuscript has had the text mutilated by some person or persons who ran over every letter with a pen making exact identification of many of the characters impossible.
Both manuscripts contain uninspired, anti-scriptural books which are not found in the Bible.
The only place where these error laden, unreliable manuscripts excel is in the quality of the materials used on them. They have good bindings and fine animal skin pages. Their physical appearance, contrary to their worthless texts, are really rather attractive. But then we have all heard the saying, "You can't tell a book by it's cover". The covers are beautiful but their texts are reprehensible.
And yet in spite of these well known corruptions, they are the basis for many new versions such as the New American Standard Version and the New International Version rendering these versions critically flawed and unreliable.
The manuscripts represented by the King James Bible have texts of the highest quality. So we see that the best manuscripts are those used by the King James translators.