I don't like what GNOME applications, such as Gedit, came to be and how they look now in Debian Testing. These colorless and borderless windows with unfamiliar layout are totally unusable for me.I know that LMDE uses Debian Testing as its base, but GNOME applications are still normal there. So can I switch to it? 
Switch from Debian Jessie to LMDE
debian;testing;lmde
In theory, you only need change the repos at /etc/apt/sources.listI did the opposite, change LMDE to Debian without troubles except in Cinnamon, no big deal and change to MATE. However, the next LMDE will be based on Stable, not on Testing.