Plymouth boot splash works with lightdm, mdm (see Plymouth Plus MDM - A Better Display Manager), and can be coerced to work with slim (see Plymouth Plus Slim). The startup splash screen running the Statler theme or any Debian theme looks good, but the closing splash screen is trashed on my system. It is completely missing the background and reveals shutdown messages it is meant to obscure, but the throbbers and progress indicators are there.
I have not found a cause, but I have developed a work-around. Change the following command in the plymouth init script (/etc/init.d/plymouth):
/sbin/plymouthd --mode=shutdown --attach-to-session
/sbin/plymouthd --mode=shutdown --tty=tty1
This directs the plymouth daemon to use virtual terminal tty1 (not the current Xsession terminal tty7). With this change, the splash appears with an appropriate background, shutdown messages are correctly obscured, and the throbbers and progress indicators are as expected. Any virtual terminal will work, as long as it is not the same terminal as the Xsession.
Hardware (via lspci) - VGA compatible controller: Intel Corporation 82Q33 Express Integrated Graphics Controller (rev 02), Driver - i915, initramfs prepared according to http://wiki.debian.org/plymouth, adding/removing FRAMEBUFFER=y has no effect.
programming and administering unix since 1976 (BSD, System III, Xenix, System V, Linux)