My older son owns two Kindles, the second one, the cheapest most basic model, was won in a raffle.
I took away the Kindle Fire since it was being used to play video game apps before bed (instead of reading a book for pleasure) and it was being snuck to read in the middle of the school day. My son was also using it for the Internet although we shut that off at the router. The first time he hacked it and the second time he let it stand, but he could still play the apps that already were downloaded.
I blogged about these challenges in detail here.
Well now I took the Kindle Fire away from him. He can read ebooks on the more basic Kindle.
I am probably going to purchase the cheap-o Kindle Fire for my younger son also just so he can have an eReader that does not allow playing video game apps.
Since my kids cannot self-regulate and since they were not getting their academic work done, I have to resort to putting limitations and restrictions on them.
Update 11/11/12: Recently I have been blogging details of our family's struggles to get basic academic work completed. If you have been reading along then this blog post will make more sense. See comments for more commentary.