My grandmother's friend uses a Kindle Fire and she likes it. She uses it for reading in her rocking chair. It doesn't have to the HD version. If you don't want the OS to be limited at all, you can go with a Galaxy Tab 2 7.0 which I own... you can find it for $200 or so and it has all the features of the Kindle Fire plus a built in IR (for changing TV channels) which is reeeally useful.
But yes, I am Android all the way, but do consider iPad Mini... yes, it is expensive. And people are like "Blah, Apple products are ovepriced". I am pro-Android myself, but Apple makes very user friendly products. Play with it yourself and ask yourself if your mother might have less stress using it... it just depends. Some people adjust better to new things than others.
Yes it's dumbed down. But that's the point. It's dumbed down. That's not necessarily a bad thing... think about the iPod, it only has a few buttons and a spinny wheel thing on it. iPhone only has one button besides power(?)... how can you screw that up?
When I did cell phone/mp3 sales a long time ago, this made a lot of difference for people.
Nexus 7 is good and a lot of people rave about the user experience and how fluid Android Jelly Bean feels on it, but keep in mind it has NO external memory... unlike the Galaxy Tab 2.
Galaxy Tab 2 has a front/back camera too if it matters, but it's not a great one.
