We present an analysis of the influence of colour distance on the user experience with choropleth and chorochromatic maps. We systematically evaluated five sequential and five qualitative colour schemes in a two-stage user experiment. At first, we conducted an online study to obtain performance metrics accuracy and response time from a large, heterogeneous population. Following this, in a controlled lab study with eye-tracking, we re-examined the findings from the online study for a subset of experimental stimuli and further assessed the user experience through an analysis of their visual behaviour. In this process, along with accuracy and response time, eye-tracking metrics fixation frequency, fixation duration and scanpath speed as well as a gaze transition analysis were utilized. In both experiments, participants were asked to compare two areas with controlled colour distances between them, and decide whether these areas were of the same colour. Results suggest that we are able to discriminate narrower colour distances than commonly used in practice, however, not as narrow as suggested in previous literature.