Privacy enhancing technologies (PETs) are regarded as an important building block for implementing privacy guarantees. However, the maturity of different PETs varies and is not easy to determine. In this paper, we present an assessment framework that allows to compare the maturity of PETs. This framework combines two rating scales: one for technology readiness and one for privacy enhancement quality. The assessment methodology has been tested in two experiments, one of them being conducted at the 2015 IFIP Summer School on Privacy and Identity Management with junior and senior researchers. We describe the first experiment and how we gathered feedback on our assessment methodology in an interactive workshop. The results were used to refine and improve the assessment framework.