Justly does Sir Arthur enjoy the reputation of one of the greatest writers of hard science fiction; but his prose is that of an engineer: it is precise, accurate, clear and--boring. It is uninspired. It is dull. It is pedestrian. In Clark's books the science and the plot have to do all the heavy lifting.
By that standard, Stanisław Lem is the greater writer. Like Clark's, his plots are good and his science is excellent, but his prose is absolutely brilliant, with occasional flashes of genius. Unlike Clark, Lem is a writer, he writes literature. Just read this fragment of Fiasco, in which the hero is traversing the great Brinam Wood--an imaginary geological feature on Titan:
Then the land changed. It was still forbidding but in a different way. The planet had gone through a period of bombardments and eruptions, sending blind bursts of lava and basalt skyward, to freeze in wild, alien immobility. He now entered these volcanic defiles. The overhangs farther on were unbelievable. The non-living dynamism of these seismic congealings—inexpressible in the language of beings raised on a tamer planet—was accentuated by gravitation no greater than that of Mars. To a man lost in this labyrinth, his striding vehicle ceased to seem a giant. It dwindled, insignificant among the crags of lava, which once, in kilometer-long cascades of fire, had been transfixed by the cosmic cold. The cold cut short their flow, and before they froze, falling in the precipices, it drew them out into gigantic, vertical icicles—monstrous colonnades—a sight that was one of a kind. It made of [his vehicle] a microscopic bug that inched past towering pillars—pillars of a building abandoned, after construction as careless as it was mighty, by the true giants of the planet. Or: a thick syrup flowing from the lip of some vessel and hardening into stalactites—as witnessed by an ant from its crack in the floor. But no, the scale was more awesome than that. It was in this wilderness, in this order-disorder so foreign to the human eye, bearing no similarity to any mountains on Earth, that the cruel beauty of the place showed itself, the beauty of a waste vomited from the planet’s depths and turned, beneath a remote sun, from fire to stone. Remote—because the sun here was no flaming disk as on the Moon or Earth; it was a coldly glowing nail hammered into a dun sky, giving little light and even less heat.
Outside, it was 90 below, the temperature of an exceptionally mild summer this year. At the mouth of the gorge Parvis observed a glow in the sky. The glow rose higher and higher until it took up a quarter of the firmament. He did not realize at first that this was neither dawn nor the illumination of a solector, but the mother and ruler of Titan, great-ringed, yellow as honey: Saturn.
(translated by Michael Kandel)