He whistles when caresses the (simpler than digibirds where you have the handy whistle, and most importantly, this whistle quickly breaks the ears ...).
He repeats what is said by pressing the button (the digibirds do not speak).
The BIG + compared to digibird: batteries. Here it comes to AAA, so they take longer than the digibirds button batteries (2 days max for the digi ...), and especially we can put rechargeable.
Petit - compared to digibird: the digibird turns the head while that of the little live pet does not move.
The Digibird is plastic, so less messy (the "little live pet" is in fact a kind of "velvet", harder to clean).