Although I have never used Qlik before I have to vote for Qlik. I think Power BI is a bit over rated, it misses many mature features that tools like Qlik, Tableau, Targit and all the others had from the very beginning. I’m not saying that Power BI is bad, also it is for free (at the momemt at least), however Microsoft pushes it a lot and there is a lot of paid content to push it. On the long run I see Power BI will be a valid options for companies, but at the moment I can and only use it for exploration things.