Your question is very broad. Not sure if there is a easy answer to that.
A report of the business value of using JBoss Fuse was just published a few days ago. I think this report may help answer some of your questions. Its a report of 6 customers of "before" vs "after" using JBoss Fuse with hard numbers of their business gains in cost benefit, performance, development time, and so on.
The report is here
And I did a blog post this morning with some of my observations from the Apache Camel side of things