An increasing number of interactive systems aim to enhance the user experience (UX) of visitors at museums, archaeological places and cultural sites. This paper presents a review of empirical evaluations of interactive systems in cultural heritage (CH) based on a systematically selected sample of 53 publications from 2012-2016. Empirical evaluations examine the degree an interactive system satisfies user goals and expectations and are inherently complex activities that require careful planning and selection of methods. The review reports on (a) interactive systems of CH in terms of: purpose, technology, cultural content and location of interaction and (b) methods of empirical evaluation in terms of: dimensions of UX, general approach, data collection and participants. The paper provides discussion, critique and outlook on issues including: extending the evaluation dimensions towards the cultural value and the essence of interactivity; placing more consideration on CH professionals; identifying new evaluation methods that balance qualitative results to evidence-based approaches.