This is, I think, my favorite Philip K Dick book so far (although I really loved Do Androids Dream of Electric Sheep). I picked it up to take a break from my re-read of VALIS. I thought I was getting tired of PK Dick because I wasn't really enjoying VALIS, but picking up another of his books with more plot has helped get me back on my PK Dick kick. 
 I found it interesting and enjoyable to be inside the main character's head and witness his confusion and attempts to sort out reality from fiction. Of course, there's some element of this in all of PK Dick's novels (or at least the handful I've read). Perhaps that's the trip that I really enjoy when reading his books.