A Qt/KDE developer has posted a technical comparison of the competing tool-kits to his blog. Looked at are various factors when developing a simple mine-sweeper program in Qt QML and Enlightenment EFL.
Compared is the development experience, development time, source code size and languages, memory consumption, start-up time, and other factors.
The conclusion? "Taking these points into account it is surprising to see QtQuick app performing similarly to C-based app made in EFL. In addition, QtQuick introduces useful features not present in the EFL app (binary-independence, network transparency, safer memory operations) without sacrificing performance (compared to EFL). Furthermore these tests can be repeated for Qt 5/QML2 which is reportedly even more optimized."