Here are some differences:
-Chat support if you have problems with your app: we have people on our website's chat and on email ready to answer your questions.
-Material design: If you move your apps over to Thunkable (or make new apps), they will look much prettier on an Android device than your App Inventor app looks, with no extra effort. Try it out!
-Google maps integration: If you look at the visualization section of the palette you will see the new google maps component.Here is a tutorial video on using it.