The rubber is of the right quality and rigidity to be easy to press while riding. As a result, if you're riding over bumpy terrain you may hear the occasional short squeak, but in general your new pet will only honk when you want it to.
At around $10 it's competitive with most other bells and whistles you can get for a bike's bars. Once the mounting system comes into play however, the value gets a little more complicated.
Firstly, the plastic wrap-around mount is made of a weak material with some cheap set-screws holding it around the bar, so it can easily brake. That's actually not so big a deal though, because if you have a modern bike that you want to put your eclectic little mascot on, it's most likely equipped with a 31.8mm diameter handlebar. This mount doesn't fit around that width, so the bottom part of the mount needs to be ditched and an alternative method (zip-ties) has to be used. I also tried mounting one off the front of the bars with a spare reflector bracket and bits and pieces of that nature, but then another problem arises, since the actual noise-maker in the horn is a small plastic sleeve which fits into the bottom of the rubber creature. This means that if the mount isn't wrapped around a bar, your creature may go mute very quickly.
As usual, the interface between the product and the bike is where this horn's value suffers. As a result, what should be a five-star-buy becomes a 3.5 star gift on a wish list. It's neat, but ideally someone else puts up the money.