Im reaching out to see if anyone has used ApptioOne and ATP for Benefit realization tracking?  We are looking to track quantifiable benefits for our initiatives within the tools and tie them back to an ROI.

Any thoughts?

You could use Action Plans to define your initiatives and tie them to ROI:

I set up some sample plans a while ago, and don't quite remember the details. It's a pretty manual process, but it can work.

I am not sure that this product/feature is actively supported. The help says it's part of Apptio BI, but in Front Door it looks like a separate product:

Maybe @Connor Kinkead or @Curtis Michael can shed more light on this topic.

Regardless of the tool support, you need to come up with the plans yourself, @Marge Schneider 
That is surely the trickiest bit, at least for us.