For a long time I have been using SLiM as my display manager on ArchLinux. It worked quite well for me, but is unmaintained since at least 3 years. Also according to the ArchLinux WiKi there are issues regarding to systemd compatibility. Also the Linux desktop is headed towards Wayland so I need a display manager which can start Wayland sessions.
So my choice fell on LightDM, which should "support different display technologies (X, Mir, Wayland, ...)" according to their website.
Installing it on ArchLinux is as easy as:
sudo pacman -S lightdm-gtk-greeter
Then we need to deactivate SLiM and activate LightDM:
sudo systemctl disable slim.service sudo systemctl enable lightdm.service
To switch without a reboot one needs to logout from the X-session, switch to a TTY with Ctrl-Alt-1 and stop SLiM and start LightDM:
sudo systemctl stop slim.service sudo systemctl start lightdm.service
After that I could login just to notice that my ~/.xinitrc wasn't getting executed, so my helper tools like nm-applet weren't running. Since I already solved that issue under Ubuntu, I was a bit surprised that I need to solve it differently under ArchLinux according to the WiKi:
mv ~/.xinitrc ~/.xprofile vim ~/.xprofile # remove the "exec awesome" line