I bought this game just after christmas, hoping it would help me get fit and do some exercise...
I have to say its done just that.
Whether you are playing on your own or as a group of friends its a good laugh. When the song involves more than one person and you are playing on you own you can decide which character you want to be so there can be more than one set of dance moves for that song. This is good as afetr a while of playing it the songs become a bit repetative. If you have your Wii connected to the internet you are able to download songs though.
I didnt realise I had zero co-ordination untill I played this game... its definatley not as easy as it looks on the tv!
There is a wide range of songs on this game all rated with up to 3 stars for difficulty.
The 'Just Sweat' option is brilliant if you want to set yourself weekly goals and it even tells you what each of the 3 targets is the equivilent of, e.g. 30 mins swimming or 30 mins running a day. To reach your goal you have to earn a certain amount of sweat points by completing songs/
The only down side of the Just Sweat option is that the levels are too spaced apart, I found level 2 a bit easy to reach the target of the needed sweat points a day but level 3 too hard to reach.
The Just Dance standard option is good if you want to practice your moves without the pressure of gaining a certain amount of points. the better you do the more stars you earn and the more of the game you unlock.

So whether your strutting your stuff or showing you have 2 left feet you will enjoy yourself.