[Note: If you don't feel like battling a whole bunch of text, feel free to enjoy our video synopsis of Punch-Out!! by using your mouse bicep to punch-click this handy link.]
The big draws for Punch-Out!! on the Wii are motion-based controls and Balance Board support -- and they're a lot more responsive and fun to use than you would find in Wii Sports' boxing mode. With the analog stick controlling your character's movement, it's fairly easy to dodge and take out your opponents. It works, but the game really shines when you're playing with the classic controls.
Punch-Out!! fans will feel right at home once they switch to classic mode. Controls are the same they've been for more than a decade, so you'll be able to get right into the action and enjoy the game. Another reason to choose classic over the Wiimote-and-Nunchuk method is speed, as you'll be a lot faster both dodging and delivering punches. It's a drawback of the motion-based controls, because you can easily push a button faster than it takes you to fake-throw a punch. Also, the motion-based controls may be surprisingly responsive, but that doesn't mean there won't be instances where you accidentally throw a punch or deliver a strike too late, which can be a big problem in the latter parts of the game.
Another issue I had with the game was a sharp increase in difficulty almost out of nowhere. The game is divided into 3 different circuits, and veterans of Punch-Out!! will likely experience what I did: eight boxers who are pushovers and then the last circuit of five, which really jacks up the difficulty. It can be frustrating and tough transition, but it's a lot better than the alternative of the entire game being incredibly easy to conquer.
But even after you plow through the circuits there's more to do, as Nintendo has finally figured out how to add replay value to a Punch-Out!! game. There's a Head-to-Head mode, as well as Exhibition matches with scenarios to complete (such as defeat Super Macho Man in Round 1, and TKO or KO Great Tiger using only right jabs). The Head-to-Head mode is fairly fun, and should replace Wii Sports boxing for most folks, but it would have been nice to be able to select different boxers aside from Little Mac.
Nintendo has done a good job of throwing a new coat of paint on Punch-Out!!, but has also taken special care to make sure the core of the experience has not been changed for Wii. This means that fans of the franchise won't feel alienated, and newcomers can easily pick up the Wiimote (and Nunchuk, if that's how they want to roll) and get into the action.