There has been some low level grumbling especially re: royalty reports. More details at Piers Anthony:
December 2007 update ... one author decided not to go POD, then discovered that the book had been printed anyway and was being sold on Amazon ... It seems the division of the money is in this order: Amazon, Paw Prints, WCP, and finally the author, who apparently receives no accounting ... a call to the owner of WCP was met with immediate hostility and abuse ... They refuse to correct errors made by their editors ... may not even send out books for review. No actual accounting on their royalty statement how many books are sold, and they refuse to answer questions about this ... if there is to be a pissing contest, bring an umbrella. Meanwhile, be wary; there is a noxious odor here.
ETA: for some interesting comments, see Karen Scott