Maui is a linux system with atomic upgrades. Problem: during typical package-based update, your system is in an inconsistent state. Solution: fetch updates and apply them into a separate copy, then reboot into the modified system. This makes updates atomic and failure-free, and it supports full upgrades to a new release without problems. mauibuild builds a live image from git repositories, based on gnome-ostree and yocto.
Hawaii is a pure Wayland desktop environment. Focuses on convergence of different environments (PC, phone, tablet). Hawaii uses QML to make this possible (different layout for different devices) – in Qt 5.2 the desktop support has improved, e.g. QFileSelector. To make the dependencies manageable, KDE Frameworks is used so the common parts can be reused in other projects.