The fact that it's not too complicated to use - you just drag & drop icons into your project! It makes my life easier so I never have any problems using this tool for design tasks like creating buttons or navigation menus etc., And when there are issues (like rendering) they're usually fixed very quickly by their support team which has been fantastic throughout our relationship thus far. Nothing really at present but if possible would love more control over what elements get exported out each time an export button was pressed- maybe even some kind of layer selection/grouping?