UPDATE: PDF/A-1 1a and 1b - A Difference Without a Distinction

In May 2011, I commented that PACER did not discuss the difference between PDF-A 1a and 1b so there seemed to be no preference for either.  Since then, PACER has published detailed instructions outlining creation of PDF-A 1a format.  In addition, some courts are adding this specification.

A difference without a distinction - may no longer be true.  It is now important to determine whether 1a or 1b is the preferred format.  Comments are invited regarding specific courts and their exact requirements.

PS: Here is a very useful seminar published on AcrobatUsers.com discussing the differences between PDF-A 1a and 1b.