I haven't really finished it yet, but I guess I'm more pleased with it than most people here. I thought it posed a decent thought experiment about a truly anarchist society. That, for me, was enough to distance it from being too much of a parallel to existing political movements and structures. Yes, the Cold War powers are there, but they're on Urras. The Dispossessed takes the political movements a lot farther than you could get from any real anarchist movement on earth; Shevek came from an anarchist society of the type that could only really exist if you build a whole new society on an isolated planet from the ground up. At points, it gets to be an interesting exploration of what kind of person that society makes.
Le Guin is thoughtful enough with the exploration that it doesn't really come across as an endorsement. You see the questionable undersides of Anarres, the points where Odonism seems to clash with human nature, it's shortcomings compared to Urras... I can see what Dala is talking about (though I don't recall encountering the feminist issue specifically, but Le Guin doesn't come across as committed to a flawlessly flattering portrait of Anarres). Of course, it could be that the book goes suddenly Ayn Rand in the last few chapters to become a wholly unbiased polemic piece that was only pretending to be socially thoughtful (I've read books like that before).