I am on my second Kindle. I had the original cheap one that was $79. The only issue I had with that was it was not back lit. The new one I use to read FR/surf the internet in bed at night or read books. I read more now than when I did not have one. It is so easy to buy a book. No going to the store, or ordering one from a secondary seller and waiting to receive it.
My wife has an IPAD, it almost never gets used anymore. She also has a desktop and my son has a laptop.
So does your wife prefer her Kindle to her iPad?
I have an iPad 1 that I have used for several years. Most of my reading is still done with books, as I read a lot of non-fiction history stuff with maps, etc. However, I do have a lot of books on my iPad that can be read with the Kindle, Nook or iBooks apps. I also read digital comic books on it. I like the iPad for comics because it is almsot the size of a regular comic book. I also use if for most of my surfing like you do with your Kindle. I can surf in bed, sitting ouside enjoying a cigar, etc.