Aside from the fact that It invokes an instance of Chromium (runlevel2?) with root permissions...
(inviting vulnerabilities)(one has already been discovered, documented, and patched)
...that Chromium instance adds 30Mb overhead to a session, from the outset!
I've stayed away from lightDM so far because pam is a hard dependency. Coming from a slackware-based distro, I'm not excited about trying to implement that. So, it's SLiM for me, or maybe lxdm
By chromium, I think you mean the use of webkit for the greeter. AIUI there are alternative greeters that are gtk (or qt) based. Unless, I've misunderstood lightdm's description from its homepage.
are there any other gtk greeters beside lightdm and gdm?
I work with Mageia cauldron and I use lxdm (lxdm was adapted for Mageia cauldron)
I found SLIM. It's just beatifull!
(login into unlevel 3 and make a startx obviously seting the .xinitrc file)
direct acces from boot to you xfce4 session no-using none *dm
xdm (the OLD but well-know xdm)
XFCE :: Arch Linux
:: Intel(R) Atom(R) N270 @ 4W at 1.60GHz
:: ntel Corporation Mobile 945GSE Express Integrated Graphics Controller (rev 03)
:: LED WSVGA of 10.1" (1,024 x 600)
i use "wdm" as the login manager which also doesn't have much dependency