I've had three separate goes with LMDE. First when it had just come out, and honestly I blame myself for that - you just don't try a distro before several months of testing by the public have passed. Video drivers wouldn't work, and it was full of bugs.
Second time just for kicks, as I have a business box that I don't really need but that's too worthless to sell, so I keep it as a backup computer and for those "ooh, new distro, let's check it out" moments. I couldn't get a positive feeling with it; things didn't quite work as seamlessly as the Mint people say, and I often found myself thinking "argh, why do I have to do this when in Debian it'd just work?". Eventually I just switched back to Debian.
Third time was when a friend asked me for something that was "like ubuntu but without the mess". Thought maybe LMDE had matured enough by then, so I installed it and we tinkered at it for a while. It was not a particularly pleasant experience. I ended up installing PCLinuxOS on my friend's laptop, and they've never been happier.