every prepackaged integration supports every integration middleware technology today. The support depends on the deployment model. Sometimes the support for a certain middleware technology may be on the road map. Please discuss this with your technical solution consultant before picking an option. You can also ask Solution consultants and partners (if you are working with one) for their recommendation based on your deployment model, implementation schedule, current landscape, in-house expertise, and business needs.
Customer are welcome to use a middleware technology of their choice
Another important thing to note is that many SuccessFactors customers use an integration middleware technology other than the ones mentioned above for business reasons. While it might cost them a bit more to implement the prepackaged integrations on a middleware technology of their choice, they take such decisions to keep their landscape simple and take advantage of existing skills within the organization..
SAP customers use many different middleware technologies
I have discussed integration middleware needs with hundreds of customers. Majority of them also use technologies other than the three mentioned above. I also found out that almost all customers use at least two different middleware technologies in their landscape.
My opinion about prepackaged integration design
Bulk of the work in any integration is usually not middleware configuration. Bulk of the work is identifying the field mapping and ensuring that the right data flows from the right source to the right target. I believe that it makes sense to create prepackaged integrations that do not depend too much on the features of a particular middleware technology. Such integration design will enable customers to switch from one technology to another, should the need arise, easily.