I saw this presentation by a customer who uses SAP, Salesforce.com and Workday. I found it useful to listen to the experience of a customer who has integrated OnPremise solutions and multiple cloud solutions from multiple vendors. The solution architect who presents talks extensively about SAP NetWeaver PI and Dell Boomi. I want to point out that both technologies are used to integrate SAP and SuccessFactors.
The solution architect says that when it comes to integrating with SAP, SAP NetWeaver PI works really well. He also talks about how SAP NetWeaver PI and SAP ABAP developers can contribute and support an integration using Dell Boomi.
Learning Curve for a cloud integration platform
He talks about the learning curve for Dell Boomi and the kind of background required for someone to become a Dell Boomi developer.