I have two relevant experiences.
I “published” my PhD Thesis with VDM. In the past 5 years, they have sold 2-3 copies @ $100/each. I think that sales are slow because I give away the thesis for free online (http://ssrn.com/abstract=1129046). I know one buyer (a lawyer spending client $), but others may be fooled. That’s a pity, but 1,131 people have downloaded my diss for free. Other students should do the same.
I also published both of my books via CreateSpace, which is not at all predatory. I agree that it can be a vanity press, but so is the corner copy-shop. The benefit of CS is HUGE to me, as it allows me to get POD at a low price ($2 or $4 per copy, depending on my book) that I can resell to others as well as sell via Amazon. I think that POD models are MUCH better for the 99% of authors who do not have name-brand recognition. I *was* under contract with UC Press but fired them for (1) no marketing plan, (2) poor technical standards and timing and (3) editorial micromanagement. I’ve outlined the advantages of self publishing (and the publishing industry in general) in these posts:
http://www.aguanomics.com/2011/10/microeconomics-of-publishing.html
http://www.aguanomics.com/2011/10/macroeconomics-of-publishing.html
