"I am in profession an actor, and my name is Wilks. When I was on the stage I mixed with all sorts of Bohemian and blackguard company. Sometimes I touched the edge of the turf, and sometimes the riff-raff of the arts, and occasionally the political refugee. In some den of exiled dreamers I was introduced to the great German Nihilist philosopher, Professor de Worms. I did not gather much about him apart from his appearance, which was very disgusting, and which I studied carefully. I understood that he had proved that the destructive principle in the universe is God; hence he insisted on the need for a furious and incessant energy, rending all things in pieces. Energy, he said, was the All. He was lame, short-sighted, and partially paralytic."
I'm not going to turn this into a Nietzsche hate-fest post. I still don't like Nietzsche, and (after having spent a little more time with his writings) haven't found much there to convince me of his greatness as a thinker . Actually, I've only heard/seen three people whom I respect really defend him: two friends who sort of share a name, and one well-respected Thomistic philosopher. The rest have said some nice things about him at times, but have largely said that he has done more harm than good (and a few have had nothing positive to say about him at all). I haven't read anything of his which convinces me otherwise, though I still haven't read enough to say that I am a Nietzsche expert, nor enough for a proper synthesis of his thought.
Suffice it to say that Chesterton's description of Professor de Worms is in fact his caricature of Nietzsche, the man who would not soften his heart and thus suffered a soften head (as Chesterton notes in Orthodoxy). But it is even better than a caricature of Nietzsche, whom a few good thinkers have admired and still more respected: it is a reflection of the many people who wanted to imitate Nietzsche's Nihilism without tempering it with Nietzsche's pessimism, or really his utter despair.
Nietzsche may be received by many today as the prophet of pessimism, or the doctor of despair. On the other hand, de Koninck has argued that Nietzsche did not quite go far enough: he wanted it all, but did not know what it all meant. And thus all that he wanted fell short of everything, just as the superman ultimately fell short of the Son of Man. Many of Nietzsche latter-day followers in turn fall short of his own desires: where he wanted it all yet despaired of getting it all, they start by wanting nothing and then end in despair of getting even that.
Nietzsche almost certainly knew that he would himself fall well short of being the superman--hence his despair and eventual madness. But Nietzsche might be credited for this foresight, since some of his other imitators failed to have this realization. The scholars say that Nietzsche would not have been a Nazi, but there were more than a few Nazis who would style themselves Nietzscheans: they would at the least co-opt some of his ideas for the superman and corrupt them to be a super-race. But the Nazis did not despair of finding their supermen, but rather embraced the idea as a sort of cult, employing every means to obtain that end: from eugenics to executions to "educational" propaganda. For all their optimism in the overman, the Nazis ultimately only succeeded in creating several under-races, in particular the Jews.
It is entirely possible--and here I can only speculate--that Nietzsche realized only too late that the real superman is the saint. Neither Nietsche's superman nor the church's saints can in the end make themselves: though it seems to me that Nietzsche's superman must make himself, whereas the saint must be conscience that it is God Who makes men and transforms them from sinner to saint. Perhaps Nietzsche knew this, and perhaps this is why he ultimately sank further into the madness of despair. In rejecting God he not only lost grace, and truth, and goodness: he also lost his only chance to become a real superman by becoming a saint.
 This is not to say that I have found nothing at all. I largely disagree with him, but he has a few interesting insights along the way, and (equally as important) a few other insights which others have inferred from him. Also, his attempts at blasphemy make the the modern God-haters pale in comparison. There are also a few places where he seems to go wrong more by way of premise that by conclusion, though of course a bad premise will likely as not result in a wrong conclusion. Thus, he shows us what the world might look like without God and without hope.