Absolutely right about the M+S designation. It's useless as far as finding a good snow tire. In fact the M+S test does not even involve snow! The new snowflake symbol is a much better way to identify a true snow tire. You can find some good info here:
http://www.tc.gc.ca/roadsafety/Topic...er/Wintere.htm
and lots of general tire info in here:
http://www.rma.org
Bridgestones: Their winter tires are based on the Blizzack design, which uses a "softer" multi-cellular rubber on the contact areas of the tire. This rubber provides great traction on ice and wet packed snow, but wears away faster-than-normal on dry pavement. Around here, you can see many sets of 2 season old Blizzack tires for sale in the various papers. I don't know from personal experience, but it seems that once this soft outer rubber wears down, the tires performance suffers.