The black and white contrast on these really does grab my newborn's attention — she'll stare at the baby animal cards way longer than I expected. I like that they're sturdy enough to prop up in the crib, and I can already tell we'll get months of use as her vision develops.
My four-month-old actually stares at these during tummy time, which is more than I can say for most of her toys. The cards are sturdy enough that she hasn't bent them yet, though I wish the box was a bit easier to pack them back into.