It's good to see how products try to join forces and try to integrate them as much as possible to facilitate the tasks of the pentesters.
Now the guys at Tenable Networks Security, Immunity and Dsquare Security are offering a 20% discount if you buy the bundle, Nessus Professional Feed+ Canvas + D2 exploit pack
An example of integration is the plugin that D2 developed, that allow you to import the Nessus results in Canvas, and analyze them to show which exploits can be used on the detected vulnerabilities.
Here is a video where you can watch this feature
Another feature is that the hashes (LM/NTLM) retrieved with Canvas can be fed into Nessus to perform local checks.
You can have more info here