Crank doesn't scale. The project is a binary file. You can't have multiple people developing screens. Its fine for small projects, anything big and it falls apart.
I used to look down on Crank like it was the next coming of Flash Lite, but after finishing a project in QML and realizing most of the heavy lifting was connecting the Javascript components to business logic C++ code running underneath through their clunky interface methods... it's pretty much the same thing.