This was one of the first toys our son showed interest in as an infant. He is now 18 mo old and still plays with it... now, he presses the button and dances along with the music. It's also very convenient because you can bring it into the car and it entertains kids on car rides, even at night because it lights up to the music.
Update: We are on child #2 and this toy is still going strong after 2.5 years (although the sticker is finally wearing off). Our second child is 4 months old and we use it in the car to calm him when he is crying. He likes the music and the colorful lights.