The so-called "majority texts" or Textus Receptus are later texts which were written in Greek and embellished by the scribes in many verses. They are not considered reliable by true scholars. Whereas the Sinaiticus and Vaticanus are much earlier and agree with the other early manuscripts.
The only reason the Byzantium manuscripts are the "majority" is because the east kept the Greek language, and the scribes continued to copy (and add to!) those manuscripts.
KJV people always cite these spurious texts and claim the variants are major in the earliest texts, when in fact the differences are neglible. It is only the later manuscripts that include Mark 16:9-20, which so clearly states that it was written long after the autographs and added to the text. There was nothing more exciting to a Byzantium scribe than adding a few words of explanation in the margin, which sadly were added to later texts. The Greek scribes did not adhere to the strict rules the Hebrew scribes did in order to preserve the Word of God. That is why the earlier texts are more reliable, because they have not been altered and changed the way the later Greek manuscripts were.
Should Mark 16:9-20 be in the Bible?
The Ending of Mark (Mark 16:9-20)
Dr. David Brown observes: "I question the 'great witness' value of any manuscript that has been overwritten, doctored, changed and added to for more than 10 centuries." (The Great Unicals).
Vaticanus
Vaticanus omits Mark 16:9-20, but a blank space is left for that section of Scripture. The following testimony is by John Burgon, who examined Vaticanus personally:
“To say that in the Vatican Codex (B), which is unquestionably the oldest we possess, St. Mark’s Gospel ends abruptly at the eighth verse of the sixteenth chapter, and that the customary subscription (Kata Mapkon) follows, is true; but it is far from being the whole truth. It requires to be stated in addition that the scribe, whose plan is found to have been to begin every fresh book of the Bible at the top of the next ensuing column to that which contained the concluding words of the preceding book, has at the close of St. Mark’s Gospel deviated from his else invariable practice. HE HAS LEFT IN THIS PLACE ONE COLUMN ENTIRELY VACANT. IT IS THE ONLY VACANT COLUMN IN THE WHOLE MANUSCRIPT -- A BLANK SPACE ABUNDANTLY SUFFICIENT TO CONTAIN THE TWELVE VERSES WHICH HE NEVERTHELESS WITHHELD. WHY DID HE LEAVE THAT COLUMN VACANT? What can have induced the scribe on this solitary occasion to depart from his established rule? The phenomenon (I believe I was the first to call distinct attention to it) is in the highest degree significant, and admits only one interpretation. The older manuscript from which Codex B was copied must have infallibly contained the twelve verses in dispute. The copyist was instructed to leave them out -- and he obeyed; but he prudently left a blank space in memoriam rei. Never was a blank more intelligible! Never was silence more eloquent! By this simple expedient, strange to relate, the Vatican Codex is made to refute itself even while it seems to be bearing testimony against the concluding verses of St. Mark’s Gospel, by withholding them; for it forbids the inference which, under ordinary circumstances, must have been drawn from that omission. It does more. By leaving room for the verses it omits, it brings into prominent notice at the end of fifteen centuries and a half, a more ancient witness than itself.” (Burgon, The Last Twelve Verses of the Gospel of St. Mark Vindicated, 1871, pp. 86-87)
Similar to Codex Sinaiticus, Codex Vaticanus identifies itself as a product of gnostic corruption in John 1:18, where “the only begotten Son” is changed to “the only begotten God,” thus perpetuating the ancient Arian heresy that disassociates the Son of God Jesus Christ from God Himself by claiming that the Word was not the same as the Son. John’s Gospel identifies the Son directly with the Word (John 1:1, 18), but by changing "Son" to "God" in verse 18, this direct association is broken.
Codex Vaticanus contains the false Roman Catholic apocryphal books such as Judith, Tobias, and Baruch, while it omits the pastoral epistles (I Timothy through Titus), the Book of Revelation, and it cuts off the Book of Hebrews at Hebrews 9:14 (a very convenient stopping point for the Catholic Church, since God forbids their priesthood in Hebrews 10 and exposes the mass as totally useless as well!).
Sinaiticus
"In the year 1844, while travelling under the patronage of Frederick Augustus King of Saxony, in quest of manuscripts, Tischendorf reached the Convent of St. Catherine, on Mount Sinai. Here, observing some old-looking documents in a basketful of papers ready for lighting the stove, he picked them out, and discovered that they were forty-three vellum leaves of the Septuagint Version. Some enemies of the defense of the King James Bible have claimed that the manuscripts were not found in a "waste basket," but they were. That is exactly how Tischendorf described it. "I perceived a large and wide basket full of old parchments; and the librarian told me that two heaps like this had been already committed to the flames. What was my surprise to find amid this heap of papers..." (Narrative of the Discovery of the Sinaitic Manuscript, p. 23).
John Burgon, who was alive when Tischendorf discovered the Codex Sinaiticus and also personally visited St. Catherine's to research ancient manuscripts, testified that the manuscripts "got deposited in the waste-paper basket of the Convent." (The Revision Revised, 1883, pp. 319, 342)
So, it looks like the Orthodox monks evidently had long since decided that the numerous omissions and alterations in the manuscript had rendered it useless and had stored it away in some closet where it had remained unused for centuries. Yet Tischendorf promoted it widely and vigorously as representing a more accurate text than the thousands of manuscripts supporting the Textus Receptus. Furthermore, he assumed that it came from about the 4th century, but he never found any actual proof that it dated earlier than the 12th century.
Dr. F.H.A. Scrivener, who published A Full Collation of the Codex Sinaiticus in 1864 testified: "The Codex is covered with alterations of an obviously correctional character—brought in by at least ten different revisers, some of them systematically spread over every page, others occasional, or limited to separate portions of the manuscript, many of these being contemporaneous with the first writer, but for the greater part belonging to the sixth or seventh century." Thus, it is evident that scribes in bygone centuries did not consider the Sinaiticus to represent a pure text. Why it should be so revered by modern textual critics is a mystery.
Is Older Better?
Bible students are often told that the Codex Vaticanus and Codex Sinaiticus are better (i.e. more accurate) than other manuscripts because they are older. So, let's examine if OLDER necessarily equates with BETTER.
The whole subject of New Testament criticism is too complex to discuss here (or for me to try to discuss anywhere!), but it is significant that almost all of the new versions of the New Testament are based on what is known as the Westcott and Hort Greek Text, or some modification thereof (such as the Nestle-Aland text), whereas the King James Bible is based largely on what is known as the Textus Receptus (aka the Received Text or the Byzantine Greek Text).
Of significance is the fact that Westcott and Hort were involved in the occult and spiritism and they both hated ("reviled" in their own words) the Textus Receptus. So, what did they do? They basically "invented" their own Greek text, which was based primarily on two very corrupt 4th century Catholic manuscripts: Codex Vaticanus (discovered in the Pope's library in 1481) and Codex Sinaiticus (discovered in 1844 in a trash can at St. Catherine's monastery near Mount Sinai).
Since the late 1800's, their Greek New Testament text has largely replaced the traditional Textus Receptus in modern seminaries, especially as revised and updated by two Germans, Eberhard Nestle and Kurt Aland. All of these men were evolutionists. Furthermore, Westcott and Hort, although they were Anglican officials, they were "closet" Roman Catholics, denied the inerrancy of Scripture, hated the Biblical teaching of substitutionary atonement, believed that all men were gods, and were involved in spiritism and the occult.
The evidence shows that both codices (Vaticanus and Sinaiticus) are corrupt beyond measure. To be honest, they are "better" in appearance, but certainly not in their content. Remember they are written on expensive vellum; so they ought to be in good shape. These two codices are older than other Greek manuscripts, but for anyone to suggest that they are more accurate is absurd. It is like someone saying "You will find the greatest TRUTH being preached in the oldest and most beautiful cathedrals of the world," or, "the most beautiful women have the best characters."
It is interesting to note that these two manuscripts are NOT older than the earliest versions of the Bible (the Peshitta, Italic, and Waldensian), all versions which agree with the Textus Receptus, the underlying text of the King James Bible. These anient versions are some 200 years older than Vaticanus and Sinaiticus; so the "older is better" argument should not be used.