I love PKD, his writing is wildly zany, incoherent, and feels like the slightest breeze would send it tumbling through the void. This unpolished writing style lends itself incredibly well to the themes of his works.
I was unable to enjoy VALIS as much as his other works, maybe because it's so well-written, maybe because it's too autobiographical. I don't quite know to be honest.
VALIS is truly a good book, but not for me. I can appreciate why it's seen as his masterpiece, his meisterstück.
Give it a read, you won't regret it, even of you aren't enthralled by it.