It's not surprising that the First Vision has become one of the faith issues that gets kicked around the Internet these days. Visions are personal experiences of one particular person, so little effort or justification is needed for a third party to doubt or disbelieve another's account of a vision. Most Mormons find it easy enough ignore or reject visions recounted in other Christian traditions without much reflection. As Steven C. Harper notes, "It is vital to recognize that only Joseph Smith knows whether he experienced a vision in 1820. He was the only witness to what happened and therefore his own statements are the only direct evidence. All other evidence is hearsay."  But if accepting or rejecting Joseph's accounts of his vision is so straightforward, why has the First Vision become so contentious for some people? Let's consider a few possibilities.
Late publication. The first published account of the First Vision appeared did not appear until early 1842. Known as the Wentworth Letter, it was published in the March 1842 issue of Times and Seasons (hence, "the 1842 account"). It is shorter than but quite similar to the canonized account in the Pearl of Great Price, the one most Mormons are familiar with and that missionaries of an earlier generation memorized word for word. That canonized account was written in 1838 ("the 1838 account") as part of Joseph's manuscript history, but not published until later in 1842, also in Times and Seasons.
The issue is whether the memory of an event that occurred 12 or 18 or 22 years earlier is reliable. As Fawn Brodie wrote of the 1838 account, Joseph "was writing not of his own life but of one who had already become the most celebrated prophet of the nineteenth century. And he was writing for his own people. Memories are always distorted by the wishes, thoughts, and, above all, the obligations of the moment."  Even the recent Gospel Topics essay at LDS.org "First Vision Accounts" acknowledges memory as an issue to be addressed, although the commentary there focuses on showing that the historical record, such as it is, does support Joseph's report that there were religious revivals in his neighborhood just prior to his 1820 experience.
Embellishment. The essay at LDS.org also addresses the charge of embellishment. "The second argument frequently made regarding the accounts of Joseph Smith’s First Vision is that he embellished his story over time." For example, the 1832 account written in Joseph's own hand refers to "the Lord" appearing to him in vision, whereas the other accounts describe two personages appearing, and in the 1835 account Joseph adds, "and I saw many angels in this vision."
So do those differing details represent embellishment or simply variation in the recital of a prior event? It is true that some details appearing in one account are not noted in the other accounts. But it's not really clear what is the standard of comparison. Identical accounts recorded years apart might be more indicative of misrepresentation than some variation in detail. How much variation versus how much similarity is permitted? The LDS.org commentary finds harmony, not variation: "A basic harmony in the narrative across time must be acknowledged at the outset: three of the four accounts clearly state that two personages appeared to Joseph Smith in the First Vision." As Richard Bushman notes, "One would expect variation in the simplest and truest story." 
The Late Arrival of the 1832 Account. To a modern reader, the 1832 account is the most interesting. As commentary at the Joseph Smith Papers site explains, "JS’s circa summer 1832 history is the only narrative of the foundational spiritual events of JS’s early life that includes his own handwriting." As the first account to be written, it is the closest in time to Joseph's experience of the vision and it is in his own hand, not dictated. By standard historical reasoning, the 1832 account should be the most reliable source, Exhibit A in a case for Joseph's reliability or at least sincerity.
But as recounted by Stan Larson in the most recent issue of Dialogue, the 1832 account was, at some point, hidden away in the President's office safe for several decades before finally being published only in the late 1960s, and then only when forced to by adverse circumstances.  So the earliest written account of the First Vision, arguably the most reliable of the accounts we have, has only been publicly available for about 50 years. Even more puzzling, this most reliable account was apparently squirreled away for 30 years during mid-century rather than being made publicly available. More fuel for the "they lied to me!" crowd, but the Church is certainly not hiding it now.
Not a Necessary Pillar of Our Faith. The correlated gospel of the modern LDS Church gives prominent place to the First Vision in the story of the Restoration. Interestingly, that was not the story of the Restoration told in Joseph's day. Indeed, clear through the 19th century the First Vision was not a central part in how the Restoration was recounted. As LDS historian James Allen put it, "the weight of evidence would suggest that it [the First Vision] was not a matter of common knowledge, even among church members, in the earliest years of Mormon History."  Kathleen Flake recounts the emergence of the familiar "Joseph Smith story," starting with the First Vision, during the first decades of the 20th century. She describes it as "not only a source of doctrine but as the modern L.D.S. Church's master narrative." 
All of this makes it clear that the central place of the First Vision in the LDS gospel is a somewhat recent development and does not in fact go back to the early years of the Church. The foundational place of the First Vision is a more recent shift in emphasis. An even more jarring perspective on the First Vision (for most modern Mormons) is suggested by Leonard Arrington.
Because of my introduction to the concept of symbolism as a means of expressing religious truth, I was never preoccupied with the question of the historicity of the First Vision — though the evidence is overwhelming that it did occur — or of the many reported epiphanies in Mormon, Christian, and Hebrew history. I am prepared to accept them as historical or metaphorical, as symbolical or as precisely what happened. That they convey religious truth is the essential issue, and of this I have never had any doubt. 
Perhaps the ideas discussed above and in the cited sources by various scholars of Mormonism are of some help to any Mormon who finds the First Vision on their issue shelf rather than their testimony shelf. I listed a few additional sources in Note 8.
Earlier installments in the Practical Apologetics series:
1. Steven C. Harper, "Suspicion or Trust: Reading the Accounts of Joseph Smith's First Vision," in Robert L. Millet, ed., No Weapon Shall Prosper: New Light on Sensitive Issues (Deseret Book, 2011), p. 64.
2. Fawn M. Brodie, No Man Knows My History: The Life of Joseph Smith, the Mormon Prophet (Vintage Books, 1995; 2d ed. revised and enlarged, orig. pub'd 1971), p. 25.
3. Richard L. Bushman, "The First Vision Story Revised," Dialogue Vol. 4, No. 1 (Spring 1969):85, quoted in Harper, "Suspicion or Trust," p. 72.
4. Stan Larson, "Another Look at Joseph Smith's First Vision," Dialogue Vol. 47, No. 2 (Summer 2014):37-62. The article includes the full text of the 1832 account as now published at the Joseph Smith Papers site, details of how the account was first published in the late 1960s, as well as discussion of how the three manuscript pages containing the account were, at some point during the mid-20th century, excised from the book in which they were bound, then several decades later reinserted back into the bound book.
5. James Allen, "Emergence of a Fundamental: The Expanding Role of Joseph Smith's First Vision in Mormon Religious Thought," Journal of Mormon History 7 (1980):53, quoted in Kathleen Flake, The Politics of Religious Identity: The Seating of Senator Reed Smoot, Mormon Apostle (Univ. of No. Carolina Press, 2004), p. 118.
6. Flake, The Politics of Religious Identity, p. 122.
7. Leonard J. Arrington, "Why I Am a Believer," in Philip L. Barlow, comp. and ed., A Thoughtful Faith: Essays on Belief by Mormon Scholars (1986), p. 230, quoted in Larson, "Another Look at Joseph Smith's First Vision," p. 62.
8. A few good sources on the First Vision that I have not otherwise referenced above include Dean C. Jessee, "The Early Accounts of Joseph Smith's First Vision," BYU Studies 9 (Spring 1969):275-94; John W. Welch and Erick B. Carlson, eds., Opening the Heavens: Accounts of Divine Manifestations, 1820-1844 (BYU Press, 2005); and Steven C. Harper, Joseph Smith's First Vision: A Guide to the Historical Accounts (Deseret Book, 2012).
Originally posted with comments at Times and Seasons.