In the Big Data era, efficient data analytics workflows are imperative to extract useful and meaningful insights. Data analysts and scientists spend an inordinate amount of time finding the best workflow via trial and error to get accurate and meaningful results that meet their expectations. We propose an Experimentation Engine that selects and optimizes the best workflow variant through continuous experimentation and having the end user in the loop. Experimentation Engine saves time in finding the workflow that satisfies the user requirements and provides accurate, useful and trustworthy results.