yeah I know GTK is for Linux but the way they act over at PHP-GTK and around the web you'd think PHP-GTK was solely written for Windows.
I doubt that it's as easy as visual programming where you draw the interface and the IDE writes the code for you.
Depends on preference, most programmers find writting the code from scratch easier than moving widgets about (more control. Visual Programming is too confusing).
This isn't really feedback, its just to see how many people want it.