The WaveBird communicates with the Wii via a small dongle that plugs into one of the console's four GameCube controller ports. It works fine, but the need to open the cover flap (on the side or the top, depending on whether your Wii is oriented horizontally or vertically) and attach the transceiver does ruin the console's minimalist aesthetic. As with the Wii controllers, the WaveBird utilizes two AA batteries; you'll probably want to invest in a set of third-party rechargeables.
As a wireless controller, the WaveBird can function on 16 different wireless channels. These channels are selected manually through small dials under the game pad and on the wireless receiver. These multiple channels are handy if you're using more than one WaveBird at a time or if you're experiencing interference or controller lag on any single channel.
Because it's modeled on the default GameCube controller, the WaveBird is obviously suited for playing GameCube games. Unfortunately, Virtual Console games are much more hit or miss. Because of the button layout, some older games can feel pretty awkward. The large A button, offset by the smaller B, Y, and X buttons, feel much different from the old NES and Super Nintendo controllers, and the pressure-sensitive shoulder buttons must be pushed down all the way to register a button press.
Unfortunately, Nintendo doesn't offer much of a choice for playing older games on the Wii. The conventional design of the Wii Classic Controller is much more suited for Virtual Console games, but it won't play GameCube games at all. As indicated, the WaveBird, Mad Catz MicroCon, and other (wired) GameCube controllers can play both GameCube and Virtual Console games, but they're not nearly as comfortable for older games. The Classic Controller might feel better, but you'd be missing out on the greatest games of the last generation, including Metroid Prime, Super Smash Bros. Melee, and Star Wars Rogue Leader. In the end, we prefer a GameCube controller because of its support for nearly every old game in Nintendo's library. The best wireless GameCube controller remains the Nintendo WaveBird.