We use Task Owner (User), under available hierarchies in the Project Task fact table...it's my understanding (and I could be wrong, but we've tested it a bit) that the name changes to whomever has clicked the "complete" button. Hope that helps
Reporting on the users who are part of an approval flow is not currently available. I believe this was one of the features you could vote for for the next release if I recall correctly.
With the present day solution, one possible method for capturing the needed reporting information is to use a multi select User header field that is only visible after the task has been fully approved.
I've seen this done in the past using two header fields:
Workspace Approvers (multi select user field)
Workspace Approval Date (Date Field)
The template approval task is configured using a template field setter to populate the "Workspace Approval Date" header field as soon as it is completed. This captures at the workspace header level when the approval task was completed.
The "Workspace Approvers" field has a condition on it that prevents it from being visible until the "Workspace Approval Date" field has a value. As soon as the Task is approved, the Workspace Approval Date field is populated, and the Workspace Approvers field is made visible to the Project Owner to populate. It is then the project owners responsibility to populate the header field with the users from the approval flow. This could also be done via the "Process Status" field, where the Workspace Approvers" field would become visible if the Process Status field is updated to "Executed" or something similar.
It may sound like a bit much to have Workspace Owners manually look up the users and populate a header filed, but it is very likley that they will need to be on the edit attributes screen before publishing to update other fields, so the additional time should be minimal.
An additional advantage of capturing the approvers at the header level is that it not only provides reporting ability, it also provides searching ability, so that you can then search for all workspaces approved by user "xxx"
I have the same request as Sandy. We could greatly benefit from knowing exactly how long an approval sits in someone's inbox.