Graphically, the game doesn't really have to look very good. Like in most other rhythm games, the background graphics are more for onlookers than actual participants. You can choose from several different characters, and the game has a handful of different background areas, like a train station, a house party, and the set of an American Idol-like TV show. All the areas look fine, though the models for the singer and backing band don't move all that much.
The pitch-recognition technology in Karaoke Revolution works pretty well.
The game gives you the option to adjust most of the sound levels in the game. The songs come with a vocal track, but you can turn that off if you don't need the assistance. You can also adjust your microphone level, crowd noise, and so on. While the game will support a standard USB microphone, the headset mic gives you the additional benefit of an in-ear monitor so you can hear yourself singing more clearly. The game also has built-in support for expansion discs, so it's conceivable that Konami could release song packs in the future.
Karaoke Revolution is a cool piece of technology, and it definitely has the potential to be a lot of fun, especially in a crowd setting. If you're a fan of karaoke, or think that enough of the songs on the disc are appealing, you'll certainly have fun with the game. But make no mistake, it's a product designed to fill a very specific niche, so if you aren't already at least somewhat interested in the subject, it probably won't win you over.