This is a really good toy.
It teaches counting up to 20 and also vocabulary. My one year old enjoys playing with it but so does my 3 year old - so all round is being used, though probably for different purposes. The younger ones will probably just enjoy the sounds whereas we can play very interactively with the three year old and feel that she is really benefiting and learning from the product.
We have our little girl singing Old Macdonald endlessly because of this toy (which although cute the first few times, isn't so great in the middle of the night!....) but she substitutes all the different animals into the song now and talks about what they eat etc.
Overall, would recommend - it is not just fun, but it is also educational whilst being fun - so many toys don't seem to be both these days.