Although it's using Romeo for unstable packages, LMDE continuously changes as it receives updates and new software. Compared to a frozen version of Linux Mint which changes very little once it's publicly released, it's not as stable. Things are likely to break more often but fixes can also come quicker. For this reason, LMDE requires a deeper knowledge and experience with Linux, dpkg and APT.
There was a major redesign of the printing workflow at the end of last year, which broke a lot of things. Some of these redesigned packages reached debian testing causing all this trouble to LMDE users. In contrary Ubuntu: with their fixed release cycle they grab all the packages from Debian unstable and fix all the bugs themselve before they release it. Neither Ubuntu Oneiric nor Ubuntu Precise suffered from these printing bugs because of Ubuntus good quality control.
This convinced me of keeping Ubuntu (Xubuntu), switching only the desktop to Xfce (since I don't like Unity or Gnome 3 shell).