After the introduction of WebCenter Sites 11g8 version, Sites provides various improvements from creation of vanity url to proxy-assets to various customization hooks. One of the new customization hook introduced was - 
RealTime Publishing Customization Hooks which describes on how one can develop a custom solution for multi-destination/multi-target destination publishing. Although official guide provides full detail, I recommend to read 
this article once.
Thus, there is already an custom solution to:
1. Publish assets simultaneously to multiple destination. Furthermore, publishing to disaster recovery server can also be included.
2. Publish audit trails: Who published what and when
3. Minimize the effort of Contributors and Publishers
In one of my previous blog post - 
Automatic Approval of assets, I provided a glimpse on how to create a simple custom solution to automatically approve assets wherein administrators have control over setting up time when approval of content should occur which is similar as configuring scheduling publishing. With this approach:
1. Content is approved automatically to targeted destination
2. Admin has choice of selecting which content type (asset type) should be approved
3. Scheduling configuration just like scheduled publishing
4. If proper solution is developed, wherein administrators can easily disable/enable System Events, update asset types required for approval, destinations, scheduling, etc; automatic approval of assets can be helpful in various scenarios.
So, now which one to choose? Automatic approval or Multi-Target Publishing?
I have listed down few points which can help in deciding which mechanism will meet your requirements.
| Features | Multi-Target Publishing | Automatic Approval | 
|---|
| SCHEDULING | Although multi-publishing mechanism provides scheduling; it fails to configure
 different time settings for different destinations.
 This may be required sometimes when a
 piece of content is required to be shown at different times according to timezone and
 place; given that
 delivery servers are located at different
 geographical locations.
 | As automatic approval event itself is separate event, administrators can set automatic approval event for different target destination
 to different time as needed, furthermore, they can also set scheduling publishing
 as required.
 | 
| EFFORT | This tasks will take only one step i.e. to build the solution and deploy it,
 that's it. Although it is one step process,
 if any regular changes required,
 it may require many changes within
 the solution; including restart of delivery
 servers which may not be desirable at all to customers.
 | Once the automatic approval element is ready which can intake assettypes and target destination as parameter, it is just matter of adding row in
 SystemEvents table. But if there is no way to update SystemEvents table
 via SiteExplorer (blocked due to security reasons), developers may need to
 build few more custom elements to add/update/delete approval events within
 SystemEvents table.
 | 
| AUDITING | As already mentioned in developer's guide and the Oracle PDIT blog,
 one can also add methods within same implementation to include
 audit trails as required.
 | This mechanism can be very helpful in maintaining separate approval logs and publishing logs can be maintained.
 | 
| NOTIFICATIONS | Publishing logs will contain full verbose output. But only those users with
 access to Admin UI can check the status and
 output. To access publish
 console from Contributor UI, will require another customization which is
 aptly described here -
 https://blogs.oracle.com/pdit-cas/entry/exposing_the_publish_console_in
 | Same customization of exposing publishing console can be helpful to know which assets were published. For approval messages, user can
 select the asset and check the status of each assets individually.
 | 
| CONFIGURATION | After custom solution is ready, configuring multi-target publishing is
 very easy. It is the same process as one would configure publishing
 destination but with few more arguments.
 | Configuring automatic approval can be tedious task as admin has to manually add/update row within SystemEvents table. But if custom solution is developed
 for adding/updating rows, then it can become quite easy for administrators to
 maintain different approval events.
 | 
| CAVEATS | One of the major problem with this functionality is that it is required to
 restart all target servers as there would be
 changes made within
 AdvPub.xml file, but it is one time process.
 But there are other
 alternatives one can take like routing the
 traffic to other delivery server
 until other is restarted or content can be served
 from CDNS until all
 delivery server(s) is/are up and running.
 Another issue is even if any one of the target
 server is down, although
 assets were published to other running target server(s), assets are
 marked as NOT published for all the servers;
 whether they were running
 or not. Thus, assets will get published again next time
 to all servers which may
 degrade performance depending on cache configurations.
 | One major problem is configuration i.e. adding or updating or deleting entry in SystemEvents table. But if custom solution is build for configuring automatic
 approval, then it is very easy for administrators. Another issue can be as it is
 more of custom solution built around WCS elements and not a separate
 customization hook, one has to make sure that during upgrade, custom elements
 are to be taken care of. Developers need to re-test the functionality again if OOTB
 approval element was changed.
 | 
So there you have it, all pros and cons of both mechanisms. There is no preferred or superior option to other. One has to weigh both the options according to cache configurations, architecture and of course, customer requirements. Furthermore, both mechanisms can be mixed and used as needed. For e.g. Multi Realtime publishing can be configured for delivery servers whereas test servers can be setup for automatic approval of content + scheduled publishing during no/less editorial activities. 
Disclaimer: 
The code and/or the configurations 
posted are not official
 recommendations and should be used at sole's discretion with proper 
testing before deploying on live WebCenter Sites systems. Cheers!!