MPEG-DASH provides an interoperable representation format for the adaptive delivery of multimedia content over the top of existing infrastructures (first edition: April 2012; second edition: May 2014). The MPEG-DASH standard is agnostic to the coding format and the DASH Industry Forum (DASH-IF) defines interoperability points for its usage with common codecs such AVC/H2.64, HEVC/H.265, and AAC. In practice, however, the content is being delivered over best effort networks, typically without any guarantees from the underlying network infrastructure. Thus, the characteristics of the end-to-end delivery environment may change dynamically, specifically in the available network conditions (e.g., bandwidth). Additionally, a variety of devices with different capabilities and users with personalized preferences are accessing these services. Hence, the quality as perceived by the end user becomes more and more important which is referred to as the Quality of Experience (QoE). This provides a definition for the QoE in the context of MPEG-DASH-based services. In particular, it will discuss means how to evaluate the QoE for MPEG-DASH-based services both using objective and subjective metrics. The core of the paper will be a crowdsourced user study how to evaluate different DASH solutions and implementations on a large scale.