campaign_monitor 6.x-1.0

Support for multiple lists.
Automatically fetches lists and fields on CM.
Asynchronous pushing of subscription and unsubscription requests. Reduces load and makes it more reliable and faster. Subscription statuses are locally available though.
Map fields to Drupal tokens, profile fields and PHP code.
Provides block per list. Provides block to subscribe to all lists at once.
Custom field values for authenticated users are automatically calculated an not asked again.