Maybe I'm just picky, but I think Mint replacing the standard Firefox icon should lower its place on the list of distros for people coming from Windows. Out of their preinstalled applications, Firefox is the one a Windows user is probably the most likely to be familiar with, and out-of-the-box they've got it pinned to the taskbar with an icon that a Windows user won't recognize. There's so many other distros where a Windows user can log in and clearly spot Firefox.