When you install on multiple machines it's going to be a pain point, and knowing that the prime focus of Canonical looks to be Unity support there's understandable concern from users that their DE of choice will be sidelined (look at the complaints from Kubuntu users over the years regarding Gnome's preferential support).

I've run Ubuntu for years on multiple machines, and took a look at Mint in the past couple of months on this basis. A well put together distro, but until they change their policy of baked-in search hijacking on the browser, I think they'll have a hard time winning over the 'droves' being talked about here.

Everything I've seen from mint is that the people switching to it can't or don't want to install something as simple as a media player or a font, let alone a whole new DE.