Our smartest cat loves it
One of our cats used to have problems with eating his dry food too fast and making himself sick - this puzzle feeder slows him down and stops him eating all his food at once. He learned very quickly how to flick biscuits out with his paws and it does exactly what we wanted.
I will add that our cat who uses this is very smart - our other cat does not know how to get food out of the feeder, even if there's something on the outside rim.