The best thing about this tool is it gives you an overview of how many people are visiting each page in our site so that we can make changes accordingly if required! Sometimes there's delay while loading pages which takes time but overall its good product!! Nothing much as such I would say other than some minor issues here nthere like slow response etc. We have used their service since last 2 years now & never faced any issue till date. They provide us detailed reports regarding traffic sources/pages visited by users within our websites or portals.