Highlights:

  * Sexy query language ie: Foo.where(...).sort(...).limit(...)
  * Scopes. ie: scope :published, lambda { where(:published_at.lte => Time.now.utc) }
  * Accessible plugin that works like attr_accessible in Rails.
  * Cache key method to make caching easier.
  * Plucky and Ruby driver upgrades
  * New option :typecast for Array keys ie: key :user_ids, Array, :typecast => 'ObjectId'
  * Far more obvious about core extensions. Now live in lib/mongo_mapper/extensions and are included in ancestors instead of just opening core classes.
  * Added an UPGRADES file which will denote backwards compat breaking from now on.
  * A bajillion little bug fixes and improvements.