Pros: blinks at night...
Cons: blinks right into the wearer's eyes
I bought the heart shaped one for Rascal to wear, since he insists on going outside day and night (he has his own door).
Put it on him and he was lit up like Christmas decoration... he didn't say anything, just sat there and suffered. It was of course blinking right into his eyes.
So the verdict is, this was designed for dogs to sit at their throat. It's, plainly said, uncomfortable for a cat to wear.