He hits some people in a profound way. I find his method of thinking really healthy, and contact with it helps me stay open and creative.
Illuminatus! blew my mind, but when I read it, I was a teenager in the ideal state of receptivity. Whatever transcendent work you encounter at age 16 is gonna leave a mark. It is goofy, on purpose, but it does have its moments.
If you're not into wacky joycean hippie fiction, some of Wilson's "How to Operate Your Brain" style writing may land better, like Prometheus Rising. Or Cosmic Trigger if you're more into the UFO and Occult strain of thought. He's kind of like a more cautious Timothy Leary.