I may be late to the Raspberry Pi party - I just bought my first one this week. The Rasberry Pi is everything that I would hope for in an educational computer: cheap enough for all children to own and based on open source software (Debian Linux, LibreOffice, lots of games, and programming languages like Python, Ruby, Java, Scratch, etc. pre installed).
The open nature of the Raspberry Pi encourages kids to experiment. RPs might not be as practical as other systems like ChromeBook that have more distributed infrastructure behind them but I think that open systems provide a better better environment for experimenting with computers.
I reformatted a 32GB memory card and installed a fresh Debian Linux image provided by the Raspberry Pi project and when hooked up to a large monitor the Raspberry Pi 2 is quite capable. I installed the RubyMine IDE and git cloned a few of my Ruby projects and loaded the manuscript for my current writing project. I find the system is surprising fast with its 4 core ARM processor. For fun I have used it for my work for the last day. Of course I am writing this blog article on my RP setup.
Our future lies in how well our educational system works. In the modern world people should never stop learning new things both for the fun of it and to enhance their careers and their contributions to society. Very inexpensive devices like the RP (the latest model costs $5) that can be experimented with provide children with a good model for a life long process of experimenting and learning.