I really liked the sci-fi writer Adam Roberts's description of Philip K. Dick's writing -

"A sense of something hidden, something underground and flourishing in the interstices, like bluebells growing in the cracks of the pavement (or blooms of mors ontologica in amongst the corn) energises his fiction. It's this something that has kept his books alive when better written, better structured and better plotted novels have fallen into obscurity around them. Which is to say that critics can, and do, point to evidence of hasty writing in Dick's works, patches of ragged or inexpressive prose, or occasional addled-head-ness in most of his books (he took a whole bunch of drugs, after all). But even with all that, or conceivably because of that there is a quality that PKD's books possess that few other books, in or out of genre, can match. It is a sort of fascinating aesthetic uncleanness, resonant and enduring. More polish would have rubbed that quality away."

Taken from this review if anyone wants to check it out.