I've been trying out the alpha and so far so good, but I have several million rows of "bookmarks" from a non-drupal site that I need to migrate into my D7 rebuild.
I've tried using the migrate_extras MigrateDestinationFlagSimple class with version 2 of Flag and it works fine (with a few teething problems), but obviously it doesn't work at all with 3.x given the changes to the database. I've tried editing MigrateDestinationFlagSimple myself to reflect the 3.x changes, but somehow I'm missing something and it doesn't work.
Are there any plans to provide an updated MigrateDestinationFlagSimple class? migrate_extras is officially unmaintained, but submitting a patch on the issue queue is all I need.
Failing that, has anyone else got a working 3.x-supportive version of the migrate_extra plugin?