Speaking from personal experience in migration battles with my wife:>

[Oren Beck]

The reality is most non-tech "appliance operators" don't give a
thought to what's in their computer. At least that's my home
experience. The migration  away from outlook to purely web based mail
was not traumatic. Firefox replacing IE has been a recurrent headache.
Largely born of UI changes breaking her learned interactions, I have
had her use my oft mentioned Kiosk install of Puppy 4.0 with an
amusing set of comments. Most notable being the frustrations over
subtle differences,

That is going to be the headache inducing leitmotif for all migration
projects if mine is any indication.

-- 
Oren Beck

816.729.3645