I'm using the GNOME 3 with Wayland and it works fine except when running a Qt application. The application behaves strangly (partial rendering, placed below Top-Bar) and some fonts are huge (e.g. title and menu bar).
I've tried changing the Qt-Theme but this doesn't affect the font size. When using GNOME on X11 everything works fine.
Using Wayland-EGL Using the 'xdg-shell-v6' shell integration
QT_WAYLAND_SHELL_INTEGRATION=wl-shell doesn't help much either.
PS: I assume it's related to the High DPI handling in Qt5: https://doc.qt.io/qt-5/highdpi.html
Update 19.6.2018: It seems to be fixed in the QT5 realase (Archlinux) of today. It shows the following log message: Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.