Has anybody used these? As a programmer, my experience with App Maker's in general has been pretty terrible. Not to say something like this couldn't be awesome

Has anybody used these? As a programmer, my experience with App Maker's in general has been pretty terrible. Not to say something like this couldn't be awesome. When I was into making Games, I used to use Game Maker all the time and it worked really well. Really simple and straightforward, but I have yet to see something comparable for apps.