The Context object is part of the wM IS API.
HTTP post is supported by a wide variety of development tools. The Context object requires coding to the wM IS API.
HTTP post allows your application to easily switch to another server, if desired. Using the wM IS API locks you into IS.
HTTP post is a well known activity, the code for which (in Java code, forms, etc.) is understood by a number of developers. Using the wM IS API requires a slight learning curve.
With HTTP post you can use exising libraries and methods that can be leveraged from various tools or your own libraries. Using the wM IS API will most certainly require new development.
As you’ve seen in your testing, using the Context object results in faster transfers (I’m assuming you measured everything from the connect to the transfer to the close) than with HTTP post.
HTH
#Integration-Server-and-ESB#webmethods-Protocol-and-Transport#webMethods