Comment 9 for bug 930488

Xristh: Yes, this patch was sent to the mailing list by its author: http://lists.freedesktop.org/archives/lightdm/2012-November/000324.html

Regarding issues reported by me - the no login prompt spawning issue was not related to LightDM at all.
Unreliable tracking of switched users is a bug that affects LightDM regardless of what underlying session management system is used. I sent a patch for this to the list, too: http://lists.freedesktop.org/archives/lightdm/2012-December/000332.html
Robert Ancell thinks, it's this bug: https://bugs.launchpad.net/lightdm/+bug/851612

There will possibly be more (and more complicated) problems with systemd support but the basic functionality is fine with the patches, in my opinion. By this, I mean multi-seat support as listed on http://www.freedesktop.org/wiki/Software/systemd/logind .