Don't buy it if you have no friends. On the upside, if you do have friends and if you're having parties then its wort...
I have to admit that first impressions of the game were not good. Although as I paid for it I give it another chance playing it in Vs mode - which was pretty good fun. Even though I did get beat .... most ... all of time by non gamers.
There's not much to say really about the gameplay itself - singing into a mic sums it up.
So if you're thinking of having a few parties over the holidays or any other time for that matter then I think this is worth getting for that. But if you're a gameplayer and only able to afford a few games every so often then I'd save my money and buy a game that you'll get more enjoyment from - at the end of the day this is just a party game that you'll turn on whenever someone new comes over to the house.