With my little experience in babywearing advocacy, though a bit difficult to get used to (for the babywearer), the kangaroo carry is by far the most enjoyable positions for our little ones.
It is no exaggeration when I say ALL babies love it, provided they are worn correctly (i.e. sitting on the fabric, NOT squatting on it). Some can even sleep in this position.
So, why the love for the Kangaroo carry? It must be because this seems to be the only position where our little ones can really look where we are looking ;) and perhaps, the secure feeling that we are always there to back them up?