Wiki says they're 'lighter and more airy' than macarons. I don't know.. to me, they taste like macarons, and like very very good ones, too.
The biscuit has that wonderful combination of being shatteringly crisp on the outside and tender, soft and almost chewy on the inside. Quite a feat for such a small biscuit! The fillings are thick and creamy and intensely flavored, not too sweet. I'd say that these macarons which are not macarons, are some of the best non-Hermé macarons I´ve tasted!