1 - Since Edgy Eft there are several reports that Ubuntu, at random times, drops your Internet connection, so you have to reboot. Actually, it happenned to me;
2 - With MintDesktop you can easily add your Home folder to the panel, add or remove Trash, Home, Computer etc to Desktop;
3 - Mint forums have a better, not-so-convoluted design, so usually you get answers to your questions more quickly, although less users connected;
4 - Mint is beautiful, Ubuntu is a little dull.
Sorry, but that's the way it is.