Re: Linux for me now - Don't confuse or prejudice new users...
I think the Mint MATE evangelism is purely down to timing. When Canonical pushed the Unity desktop into Ubuntu it was a transition from the GNOME 2 desktop as the "default" (other *buntus were of course available). At the time MATE was the closest thing to GNOME 2, and Mint was the distro that had managed to get it pretty slick - so a lot of people jumped from Ubuntu / GNOME 2 ---> Mint MATE to maintain the same familiar DE feel.
Personally, I'm liking the way Cinnamon is looking in the latest Mint release (17.2) - they've certainly knocked off some final rough edges since the last time I dabbled with it a year or so ago,
You are correct in the assertion that a DE is just a DE, the slightly more skilled will graft whatever DE of choice onto favoured distro and get on with life. However, many people just want a distro / DE combination that just installs and runs of the shelf without knobbing about. Now Canonical has their official MATE distro rolling perhaps people will move back. Or maybe not as the whole search scope / lens phone-home behaviour thing did them no PR favours at all (even if it was in fact trivial to disable and only affected Unity anyway).