For those of you who are wondering about the bottom row of buttons, I wrote up a more detailed hands-on devoted solely to them after using a Japanese unit, you can read it here:
http://www.n-sider.com/blog/2012/07/fingers-on-with-the-tiniest-thing-i-like-about-the-3ds-xl
http://www.n-sider.com/blog/2012/07/fingers-on-with-the-tiniest-thing-i-like-about-the-3ds-xl