MEPIS Gnu/Linux is a distribution based on Debian Gnu/Linux. The unique nature of MEPIS Linux makes it an ideal foundation for developing a custom version of Linux for large scale deployment. MEPIS is available to work with integrators and end user clients to develop privately branded and optimally tweaked Linux configurations.
One of MEPIS' advantages over Debian is its install: MEPIS installs Debian in an easier way than Debian does: it is completely graphical (except for the initial boot/install screen) and auto-configures and auto-detects a variety of hardware.
Currently, it comes as a two CD set based on Debian Sid, the "unstable" branch of Debian. CD one is a live cd that lets you run MEPIS Linux right off the cd without installing, or it can be used to do a full install. CD one can also be used as a recovery CD as well. CD two is a package CD that has hundreds of MEPIS ready packages on it.
(Debian Sid/Unstable, curiously, is not generally that unstable, it is just that at any one moment there may be broken packages in unstable, but they are usually fixed within a day or two. It uses more up-to-date programs than the stable and testing branches of debian).
MEPIS uses the apt-get system to manage its packages and download its updates. You will find this easy to use, easy to manage, and easy to configure. You will also appreciate the KDE graphical interface for package management, which is just as easy to work with as command line apt-get.
You may find MEPIS easier to use and install Debian if you are strapped for time and/or your experience level with Linux is low. Or just that you like to discover new distributions. MEPIS won't disappoint you at all and will more than often detect about any hardware you throw at it.
In fact, finding a new distribution is exactly what Warren Woodford did when he started work on MEPIS... he got tired of finding distributions that didn't work for him.