You see a summary of which invitees have viewed the events and which have accepted or declined the invitation.
You can save lists of invitees to re-use another time. You can invite your JomSocial or Community Builder friends as a group.
You can setup a list of users to autoinvited to each newly created event.
You can make events private to invitees to that non-invitees don't see the event.
The invitation message can be customised on an event by event basis.
A demo video of this functionality is available.