The best thing is that it's free to use, you can make any kind of map or visualization as per requirement without paying anything for using this software tool which makes my work easier than before! I have used only one other similar product but i find heatmap very easy in comparison with them due its simplicity so far everything goes smoothly even when we are doing our analysis or data mapping then also no issues at all!! Nothing much yet nothing negative too about openheatmaps if anyone has got some suggestion please feel freeto share those suggestions because they will be helpful to me regarding future improvements!! It helps us visualize large amount of information easily from different sources like excel sheets etc.,.