For both her, my mother, my mother-in-law and my my step-mother-in-law it is great. From their perspective they click on Firefox, thunderbird/gmail link, OpenOffice, Skype , etc they get what they expect.

Only unlike when they were running Windows they don't have to call me over every 6 months to de-worm their sick machines. They all use Ubuntu in gnome-fallback mode (so it looks like gnome 2.x). Now days I only have to deal with rare hardware issues from my family's machines (and PC desktop are easy as hell to service).

P.S. Reflecting I think Linux is actually ideal for very technical users (programmers/sysadmins/etc) and very basic users (icon clickers). I think "power users" are actually the people who have the hardest time. They have a use case that requires more leaning than the basic users one, and can't just figure it out intuitively like the technical because they don't understand how everything actually works like the technical users do.