The best thing that I like about this software is it's ease of use. You can easily get used to its features in few days. And also you have different modes for testing your website/app so it makes things easy when we need to test our apps or websites in real world environment with people who are not aware of what they're doing while using them. Nothing really as such. Sometimes it just takes time if you don't know how to navigate through all the options present in the interface. We've been testing our app by having users from different locations (like USA) where there may be some cultural differences. So at times, sometimes there will be an issue in recognizing the face or facial expressions which could lead to wrong conclusions being drawn. We had issues related to testing of an AI bot application.