The best "stuff" comes out when the sharks bite each other. Here is a complaint in the case of Ocwen Loan Servicing, LLC v. Mortgage Electronic Registration Systems, Inc., No. 1:08-CV-00824 (E.D. Va 2008). It states, among other things, that the "MERS system is also essential to the foreclosure process, since mortgage servicers seeking to foreclose on defaulted mortgages that are registered on the MERS system must obtain an assignment from MERS in order to commence foreclosure proceedings."
You can read more here:
The case was ultimately withdrawn by Ocwen after the court denied its TRO motion.