Pointless personal anecdote: when I was a kid, I read the first book of Le Guin's Earthsea series and asked my dad to find the second one for me next time he was at a bookstore. The game of telephone between me and whatever hapless Barnes & Noble employee he relayed this request to ultimately resulted in me receiving a copy of The Left Hand of Darkness instead. Having deeply internalized the sexual mores and purity culture of my fundamentalist upbringing, I was scandalized when I read the back cover of the book (hermaphrodites portrayed positively?!?). Reading it would clearly be immoral, so I promptly asked my dad to return it to the store. (Years later, after his death, I came across that copy, which he'd evidently stuffed somewhere out of sight to placate me.)
I revisited Le Guin's writings in adulthood—freed of the compulsion to judge books by their covers—and The Lathe of Heaven and especially The Dispossessed convinced me she was brilliant. But it took me a few more years to get around to this one. I like it but I don't love it.
Some things I like about the setting:
That I was not dueling with [the king] Argaven, but trying to communicate with him, was itself an incommunicable fact.
As in many of her writings, there's a melancholy tone and a tendency to present the universe as fundamentally static or cyclical. One manifestation of this is the Gethenian calendar system, which relabels all its years every year so that the current year is Year One:
The people of Winter, who always live in the Year One, feel that progress is less important than presence.
I think when novels downplay the significance or possibility of progress like this, it makes them feel more "literary”, by implying that the themes under discussion are timeless—that life at most times in most places is characterized by roughly similar patterns of joy and suffering. Some of my favorite novels take this perspective, but it's worth remembering that it's a highly speculative perspective. The actual history of life on Earth is one of radical variation and change, where much of what makes up our conception of ordinary life has existed for a few centuries or less.
Le Guin's faintly fatalistic attitude is also on display in the Gethenian Foretellers. The Foretellers can accurately predict the future, but seem largely unable or unmotivated to apply this ability productively.
"You don't see yet, Genry, why we perfected and practice Foretelling?"
"No—"
"To exhibit the perfect uselessness of knowing the answer to the wrong question."
The main distinctive thing about Gethenians is that they’re sexless most of the time, only temporarily becoming male or female—and sexually active—during their monthly "kemmer" period. How does Le Guin think this would affect society? Beyond the elimination of rape and gender-based discrimination, she also points out:
There is no division of humanity into strong and weak halves, protective/protected, dominant/submissive, owner/chattel, active/passive. In fact the whole tendency to dualism that pervades human thinking may be found to be lessened, or changed, on Winter.
She does not predict visitors from other societies would find it easy to adapt, though:
A man wants his virility regarded, a woman wants her femininity appreciated, however indirect and subtle the indications of regard and appreciation. On Winter they will not exist. One is respected and judged only as a human being. It is an appalling experience.
There are no wars on Geth, suggesting Le Guin thinks that a society without a division of sexes would differ from ours in more ways than just the absence of the sorts of evils that inherently depend on such a division. (Compare with Nicola Griffith's Ammonite, where a society without men is essentially the same as a society with them.). But surprisingly, Le Guin doesn't attribute this to the elimination of humanity's violence-prone male sex; Gethenians still engage in all sorts of small-scale violence and murder. Rather, "[t]hey lacked, it seemed, the capacity to mobilize." She doesn't fully commit herself to saying this is a consequence of the reduced role of sex in Gethenians' lives, but still, I find it a strange suggestion. Do our sex drives generally push us to act more cohesively in large groups? The opposite speculation seems at least as plausible to me: that the sex drive is a destabilizing force which frequently undermines collective action by pulling people in conflicting directions.