I don't have time to read this now, but this old post by Glasner comes highly recommended by JP Koning. Murphy defends Sraffa in the comments. In anticipation of a fall project I've been thinking a lot the last couple weeks about whose business cycle ideas have done a better job applying Wicksell: Keynes or Hayek? When you bring Sraffa in, though, you're forced to ask yourself the question "what's the value of applying Wicksell anyway?". I do think there's value in Wicksell, but I think Sraffa's point about multiple rates of interest needs to be considered. I think you consider that point, though, by calling those multiple rates of interest "marginal efficiencies of different types of capital" and reserving the concept of "interest" for money (even then, of course, you've got lots of different time horizons and default risks to worry about). We can still talk about Hayek with all these adjustments (and I'm going to try to). I'm not one for throwing the baby out with the bathwater. But there were a lot of rough edges to work off with Hayek, and whereas Keynesians seemed to work off their rough edges over time Hayek just seemed to drop out of the conversation. I will confess, though, that I don't know Sraffa's critique nearly as well as I know Hayek or Keynes (and even with Hayek I'm not familiar with much of the PTC stuff - which is something I ought to remedy).