Just finished the book! Sorry ilex, but I didn't really like it much. What I perhaps liked most about the book, I think, is her prose - she has a poet's way of describing certain feelings. There were more than a few passages I found quotable. I wouldn't call it consistent though; sometimes she seems to hit the mark perfectly, sometimes she decides to ramble on for half a page for no good reason than poor editing, probably. She has an intimate and great scene between Shevek and his wife, but also has a scene with him getting drunk, ejaculating on a woman's dress and puking himself. (She is also very fond of the word 'decad'.) It annoyed me that Shevek was often painted as stupidly ignorant just so Le Guin could expand on more of her world, but that can be forgiven. The Sci-Fi-Science(TM) she has Shevek babble read like someone mocking physics instead of adoring it in all its complexity.
Other than Shevek, her characters are believable, although they do not do much beyond fit a stereotype and deliver some neat lines of prose. Something else that can be forgiven is her social/moral/political commentary. Viewed from 2019 I'd say they are well-trodden at best and annoying at worst. Backintheday it was probably much more groundbreaking and it probably resonated with the counterculture, so it's hard to judge her for that. But since 80% of the book is exposition on these two opposing worlds of social anarchy and capitalism, it really stifled my enjoyment of the book.
My biggest beef, though, is her devotion to exposition by telling, not showing, combined with the lack of a good plot. There is a truckload of exposition that isn't woven into the story beyond her characters uttering or thinking about the exposition. Usually, there's more than enough opportunity to weave that into the plot, but since her plot is also utterly thin, there's not much to play with. Guy goes to planet, bumps into another culture for, has a revelation or two and comes back. Instead of putting in the effort to actually have tension within those steps, she prefers to pingpong the reader from consequence-free situation to consequence-free situation. Instead of making the geopolitical pressure a central part of the book, she has a meeting in one of the last chapters that resolves with a disappointing fizzle.
I feel like this could have been a short story a fifth its length and that would've been much better.