In addition to bringing his imposing mug to your Mii Plaza, Reggie also has a puzzle piece for Puzzle Swap and can be used as a level 5 hero in Find Mii. This probably goes without saying, but his character kicks ass. See him in action after the break.
Update: Joystiq reader Staeton notes that Reggie isn't the only special Mii floating around. Nintendo president Satoru Iwata is making the rounds as well.