One can actually skip the integration Engine to integrate with Web Services (SOAP 1.1/1.2). PS internally does use it for both Tools and Apps (SCM). A few examples - PS UDDI Config, IB Pagelet config.
1. One can avoid setting up Nodes/Routings. Routings being the major culprit in Integration Setups.
2. Also, one does not have to bother about Sync Logging..
3. Best of All, difficult for someone to identify
1. Difficult for a person to troubleshoot. But, thats exactly the reason "ConnectorRequest" has been made.
I have this code running for most of the Web Services available on XMethods and StrikeIron, and works like a Gem