Here's how it stacks up to the Nintendo DSi XL. Note that it trades a smaller footprint for a bit of a thicker casing.

Nintendo has changed up the layout on the top side of the 3DS when compared to the DSi XL.

The charging port has been moved to the right side and contacts have been added presumably for the charging cradle, the stylus hole is now next to the game cartridge slot, an IR sensor window has been added, and holes for a strap have been moved to the bottom.