A little tool I wrote at work: Xorcom-nspawn: A wrapper around #systemd-#nspawn guests with some minimal configuration:

http://git.xorcom.com/cgit/tools/xorcom-nspawn.git/

Assumes hosts uses #NetworkManager (using nmcli) and guest uses #Debian's #ifupdown. Handles autologin to the guest, and handles creating two network interfaces on guest:
* One direct channel to host
* One bridged to local network

All in all systemd-nspawn is quite nice.