Re-reading The Man in the High Castle after many years certainly offers a glimpse of why Dick fans like RAW's work, and vice-versa. High Castle is written from the point of view of several characters. They struggle to figure out what the hell is going on, particularly because in many cases things are not what they seem. (Are the "genuine" American artifacts the Americans sell to the Japanese for high prices all a bunch of fakes? In one scene that made a big impression on me the first time I read the book, a Japanese presents a Mickey Mouse watch to the visiting Mr. Baynes, and Baynes wonders whether the gift is serious or a joke.) The characters are very paranoid, with good reason. They can never tell whether another character is telling them the truth, or bullshitting them. The characters live in one universe but are aware there could be others with a different reality. They can change their realities by simply moving to another area in the U.S. It's a really eerie novel.
The Man in the High Castle won the Hugo award (Dick's only Hugo!) at Discon 1, the World Science Fiction Convention held in 1963 in Washington, D.C. One can't help but feel a rush of affection for the Hugo voters for honoring this fine, weird novel. (The other nominees that year were The Sword of Aldones, Marion Zimmer Bradley; A Fall of Moondust, Arthur C. Clarke; Little Fuzzy, H. Beam Piper, and Sylva, Jean Bruller. Perhaps Dick was helped by a relatively weak field.)