In the beginning of my qlikview work I used a right navigation but wasn't happy with them because objects could overlay the navigation. I created then various show/hidden methods to switch different navigations respectively to switch between navigation and chart-objects but many users struggled with this kind of usability.
Therefore I switched by the next major release to the left and it worked without noticeable problems. Nevertheless I discussed this topic by the planning of our last release with rbecher and in the end I switched to the right navigation again. Essential for this was the circumtances that I now use containers for most of the charts and navigation-elements, too so that there are no problems with overlaying other objects and the fact that the most users are right-handed so that it's more comfortable for them to come for the navigation from the right side. Especially by using touch devices is it an advantage that the user could immediately see the result of his selections which he would cover if they were on the left side.