I don't know why, but I'd never got around to reading this, so in my latest Amazon order I thought I'd take a punt. I'm about two-thirds of the way through, and what really strikes me about it is the elements that really aren't that controversial. With the benefit of 60 years of hindsight it's clear that a key part of his argument - that planning leads to totatilitarianism - was wrong. Lots of states tried it to a greater or lesser extent whilst managing to maintain political freedoms. Given that the book was aimed at a UK audience, his predictions look particularly wide of the mark.
That said, some of his arguments about the drawbacks of planning, including the impact on individual freedoms, ring true. In addition it's notable that Hayek is clearly not a loony libertarian, as he stresses the need for a state to carry out core services, including the provision of a minimum income and (so far not very well defined) social services. He also makes a clear argument for the need for regulation in order to address externalities (I might actually use one of the passages when he discusses this in order to wrongfoot Rightie opponents of environmental legislation).
I haven't got onto the section about 'the socialist roots of Nazism' yet, so maybe I'll dramatically shift my opinion, but so far I'm surprised by how uncontroversial I'm finding it, even where I don't agree with him. From the pespective of early 21st century capitalism, where central planning by the state has been removed from many areas, it looks like he has won at least part of his argument. And there is no serious expectation of a rematch.
One final thought occured to be whilst I've been reading it. I genuinely don't get the rather Hayekian liberal Rightie attacks on the NHS for being obsessed with 'targets' and the extended criticism that it is too centralised. It's not that I don't think that these points have some validity, it's that I don't think that they apply solely to the public sector. In my experience private sector organisations are just as capable of measuring the wrong things, and creating perverse incentives by setting targets. What's more they often seem to spend a lot more money learning this lesson. Therefore don't Hayek's criticisms of the inefficiency of planning apply to any large organisation, not just the state?