You should ignore hearsay and Usenet posts and use some objective information.
The MaP scores were originally developed by the Canadian Waste Water Association
a decade or so ago. They've since been spun off into a separate organization.

http://www.map-testing.com/

It's important to ignore MaP ratings on boxes or from manufacturers and stick to
the reported scores. Some less than repuatble companies create their own MaP
rating.