I only have experience of Kindermusik, which has been very positive. I think it does provide more stimulation than can be provided at home: lots of people singing together, a whirl of activity, sounds, colours and action. I think it has made music seem more exciting to my baby than it otherwise would have been, had I tried to do the same things myself at home! She is now 13 months and it is lovely to see how thrilled she looks when I put music on at home. The classes can be a bit too intense for younger babies under 6 months.