The tool is very easy for use even when not experienced in data visualization or analytics, it's really intuitive! I can't think of anything bad about this product so far as we've used only basic functionality like creating charts from CSV files uploaded by customers (no API).
If there was an option available that would let me have more control over how my graphs look - maybe some kind customization options? It could be nice if they added such feature but at least now everything works well enough without need to get into complex coding/data manipulation stuffs just because i want advanced graphical representation of customer feedback gathered through our surveys etc.. We're solving problems related e-commerce site design using screen lab tools and providing reports back to project managers who then make decisions accordingly regarding changes made within website layout /design before going live again after testing period has passed :) Easy user friendly interface makes life easier especially since most people involved here do NOT know much programming language nor.