From KDE Community Wiki

QtQuick ultimately separates model and view. runtime in one language, model in something else and view in qml currently you can use stylesheets - hard in qml all components could be scripts

completely skinnable apps (yay). the most difficult part in qt UI is layouts. in qml we have anchors: e.g. rectangle{

 height = ...
   anchor.left = rect.left

} full control of any objects, and child objects are affected. threaded model ==> careful with multiple animations nasty things: communication between c++ and qml, easy to expose c++ stuff, but exposing things from qml to c++ is *very* difficult note: in qml you're still using stylesheets: we'd need an oxygen qml style raster rendering works very well, X11 sucks you can do custom delegates (this *could potentially* be seriously interesting for our playlist)