The way he subverts the old "Mars is a land of romance and adventure" cliche, is both genius and intensely saddening. The way he develops every character, with their own neuroses and heroic elements is great, and even the Palmer Eldritch/immature godlike being character is revealed to have several dimensions to him, and is not painted as some ancient evil, but instead as a well intentioned idiot who happens to have cosmic powers. This book is filled with psychedelic tripping, and its gleeful hops through time, space, and relative dimensions almost make this a kind of Wrinkle in Time for 1960's LSD enthusiasts. My main issues with this book include that the plot doesn't really pick up until the protagonist arrives on Mars, and the hallucination sequences are definitely on the incoherent side. They make sense, but not enough to remove the sense that you yourself may be on psychotropic drugs.
But if you're ready to take an unhinged thrill ride into the imagination of Philip K. Dick, and want to try some sci fi that's a little different from your run of the mill space opera, jump down the rabbit hole with Palmer Eldritch. You might just enjoy it.