Nowadays, the app stores host a variety of mobile health solutions. Smartphone users can choose from tens of thousands of applications, designed to prevent or manage certain diseases, or induce behavior change to improve health and life quality in general. However, the value of most applications remains unclear, as they stop short from documenting adherence to medical evidence. We review the fundamental mobile health challenges and propose Mobile Quality of Life Lab (mQoL), a mobile health platform which addresses the identified challenges and leverages recent developments to facilitate the deployment of much-needed longitudinal, multidimensional, evidence-based studies that are minimally obtrusive for the participants, yet provide high value in terms of the collected datasets, as well as potential for behavior change towards improving Quality of Life.