Here's a PDF from Webhire. I found it interesting that manual recruiting processes and automated TAS were not significantly more different in the type and quality of the metrics they provide. In all honesty, I don't think that this survey measured the "quality" of the metrics.
For example, if we talk about measuring the cost per hire, most manual systems will miss some hard dollar costs and most soft dollar costs. However, an automated system will be able to capture these. One example being the cost of the interview - the automated TAS will measure the salary spent on the interview, whereas the manual system only recorded the cost of lunch during the interview.
I simply thought Webhire could have done a much better job "selling" their case.