The Active Directory Recycle Bin is the newest, and most reliable way of restoring objects into active directory. In the past, you could use an Authorative Restore of the object. The big problem here is that you would have to take a domain controller offline to do it. You also had the ability to re-animate tombstoned objects. When you delete an object from Active Directory, it is tombstoned. That means that it is no longer available for normal Active Directory operations and nearly all of its attributes are cleared. Recovering these objects meant that you had to manually re-apply the attributes like group membership.
With AD Recycle Bin, you have up to 180 days to bring it all back. For many, the draw back is going to be the requirement of all Domain Controllers running Windows Server 2008 R2 and the forest functional level of Windows Server 2008 R2.