The critical response to Proudhon’s work during his lifetime was extensive. Much of it was also relatively uninteresting nay-saying and sectarian quibbling, but certainly not all of it. And I think that, in general, anarchists are really only aware of a few key responses, such as Marx’s Poverty of Philosophy and some of the feminist critiques, which have remained interesting because of subsequent debates.
One of the things that the increase in digital archives has changed dramatically is the accessibility of many of the early responses to Proudhon. I’ve started working to dig out as much of this critical material as I can find, and have listed the results of that research on the Proudhon Library site. There are some obvious omissions and probably a few errors, and there are lots of article-length responses still to add to the list. But I think even this small beginning to a very big job helps indicate the extent of the debate of which Proudhon put himself at the center.
There are links to electronic texts, where I could find them, and some of this material is at the very least a lot of fun. Enjoy!