The first thing that needs to be said is that this game is huge. It has a competent single-player experience as well as some modern additions to the multiplayer formula of old. That said, it's a mixed bag, combining the best of the old, along with some new. But not everything is roses.
The Subspace Emissary, the game's big single-player campaign, is one of the first things you'll want to dive into. As a primary means of unlocking characters (and padding out the game a bit), it's about a 6 hour affair that liberally douses the player in poor platforming and monotonous combat scenarios that are incredibly easy. It may be cool to have all of the Nintendo characters duke it out in one epic conflict, melding together franchises that really have no business being together (although, it's pretty cool to see Link and Yoshi teamed up, along with many others), but in the end The Subspace Emissary provides more chore and bore than the fun galore Smash Bros. is known for. This portion of the game best serves as a means to unlock characters and give those without friends (or an internet connection) something to do.
But, honestly, who really buys this game for The Subspace Emissary? It's all about the multiplayer action and the fan service roster. And, as one would imagine, the game delivers the best multiplayer action on the console (and then some).
Before I get to the gameplay, however, the controls warrant discussion. The 4 available control schemes (Wiimote alone, Wiimote and nunchuk, Classic controller and the GameCube controller) offer a variety of choices to the brawler, but, for me, the GameCube controller is the best available option. The Wiimote alone is suitable, but with the throw button being assigned to the - button, it's hard to pull that off in battle. And, when using the Wiimote alone, the block is delegated to the B trigger, making it hard to access in the heat of battle. As for the Wiimote and nunchuk, I've found a few issues. For one, you have to turn the ability to jump by pushing up on the nunchuk's analog stick off, or else you'll accidentally start jumping when you mean to do something else. Also, the lack of ridges on the face of the analog stick on the nunchuk caused my thumb to slip constantly, becoming quite the nuisance when fighting off three foes (especially on the smaller stages like Smashville). As for the Classic controller, it feels better than the Wiimote and nunchuk, but the analog stick is the same as the nunchuk's. So I would suggest using the GameCube controller. Your mileage may vary, however.