The revelation from Jesus Himself was unique, because not only was it purely God's message (as was the case with every other inspired writer) but it was also God's personality through which the message came. the personality of Paul, Peter, John and the other Biblical writers is clear in their writings. yet in the revelation from Jesus we see the personality of God.
David Guzik commenting on Hebrews 1:2 "In these last days He has spoken to us by His Son"
Hebrews, Enduring Word Commentary Series, pg 12, 2004