Faith alone, in the Word of God is enough.
While I agree with your statement, our experience should at some point validate our faith. I started reading scripture as a young child, and the NKJ version of the bible was the first "adult" book that I'd read. I was really only interested in the Old Testament passages that were obviously about Jesus, such as Isaiah 53 and psalm 22, but found most of what I read to be confusing and difficult, if not impossible to understand. My friend and brother from another mother, Jerome, patiently answered my more difficult questions from scripture (and later confessed that he gave answers which simply came to him on things that he either hadn't understood or considered.)
I became convinced of the perfection (complete self agreement) of the scriptures before I was convinced of the person of God as revealed in Jesus Christ, but when I sought him in my own desperation (somewhat like the main character in "pilgrims progress"), He found me ready to receive Him.
My faith is not based upon my experience, but my experience validates my faith.
Is it so strange that an agnostic or atheist, having rejected what they'd heard from men, should be turned around by the Spirit of God in some vision or apparition from Him? I find no biblical precedent for Satan exalting Jesus Christ as Lord and Savior, and the few passages that mention demonic revelation of God's Holy one, also have the context of fear of judgment, not of grace and salvation.
I've heard and read reports of many conversions to Christ from the Islamic world based solely on dreams and visions. Are we to discount these conversions, many of which have lead to martyrdom, because of the unusual methodology of God in these circumstances?