For stats, the Security Operations Efficiency (workbook, built-in to the Incidents blade) has MMTR and MMTC figures plus much more. The Playbooks Health workbook is also useful, to see how Playbooks are performing. I'm not sure about the 'quality' part of the question though...I guess if you are trying to measure data enrichment, if these are from Playbooks, you could measure frequency and say "5 playbook ran today that enriched the output", however was that "quality" info...maybe depending on what the playbook was doing?