Linux Mint vs Ubuntu
Linux Mint and Ubuntu are Linux distributions. Each is a simple package with a wide variety of software — they aim to include free and open source software applications for all common desktop-software needs: text editing, image editing, and web browsing software is included along with many other programs. By default, Mint and Ubuntu use the GNOME desktop, which means that these distributions' applications and the "background" software on which they depend are largely the same.
(edit: Since Ubuntu 11.04 it has shipped with the Unity interface which is unique to Ubuntu)
(edit: Since Linux Mint 13 it has shipped with either the MATE or Cinnamon desktop environment as default)
Linux Mint received a lot of attention when Mint 12 was released due to its surpassing Ubuntu in the Distrowatch.com page hit rankings. Ubuntu's Unity interface has received a lot of negative attention and Mint has been lauded for its conservative approach, moving forward with modern software but still keeping the user interface comfortable and familiar.
(edit: Since Ubuntu 12.04 improvements in, and increased exposure to, Unity have resulted in a lot of positive attention.)
 Proprietary File Types
Linux Mint offers an Ubuntu-based system which adds further refinements for ease-of-use in standard configuration. The standard configuration of Linux Mint comes preinstalled with Adobe Flash Player, software to read proprietary files such as "wmv" files, and other software which may make it easier for inexperienced computer users to use the system without making any changes. Ubuntu Oct'10 and April 2011 releases included proprietary filetypes such as "wmv" by ticking a box, much simpler than earlier releases of Ubuntu. The OEM edition of Mint does not include this software for reading proprietary files.
Some applications like java etc will come installed in Linux Mint by default, whereas Ubuntu requires the user to install them.
 Release schedule
Ubuntu and Mint are released once every six months. There is a one-month delay between a release of Ubuntu and a Linux Mint release based on that version of Ubuntu. This means that, during that month delay, the latest version of Mint will be missing the very newest software features available on Ubuntu.
 Upgrading attitudes
Mint recommends a fresh re-installation for each release, so making backups is 'essential'. (See How to upgrade to a newer release.) Mint also prefers safety, and does not recommend installing a new release until you have checked the stability of that new release.
Mint includes a customized menu rather than the standard GNOME menu. The Mint menu is likely to feel familiar and comfortable to many Windows users, while the standard menu for Ubuntu is more similar to the Mac OSX menu.
No version of Linux Mint as of Jan´11 offers the features of *Ubuntu´s "alternative" CD´s, which automates the creation of encrypted volumes, RAID partitions, and Logical Volumes.
As with most Linux distributions, advanced users are still able to set up their partitioning scheme manually to make use of features not automated by the installer, such as the above.
Ubuntu is arguably the most popular Linux distribution; however, according to distrowatch.com, Linux Mint gets more pagehits than Ubuntu does. As such, it's probably compatible with more third party Linux software than any other distribution.
Linux Mint is a well-known derivative of Ubuntu. Because they are so similar, nearly 100% of Ubuntu-compatible software will also be compatible with Linux Mint.
Both distributions are very similar and are effectively the same in everything except:
- Ubuntu has an expert installer with support for advanced partitioning schemes.
- Linux Mint includes support for additional media formats, which were left out in Ubuntu due to software patents in the US.
- Different visual theme and panel layout.
- Linux Mint-specific utilities not available in Ubuntu.
- Different programs installed by default.