there are a few features that exist on the IOS Application that is missing on the WIndows/WEB Application. for example I am missing the ability to fill in forms and drawings that I made. also, the ability to have several documents open in the same app. I can also not erase notes just by scribbling over them, which might be a problem for Lenovo and also there are just way more possibilities to customize the Pen on the Tablet App.