When I first opened the package, I was disappointed by the plug mechanism. It's basically just a piece of plastic you manually slide up and down the side to stop the flow through the funnel. I guess I expected it to be spring loaded or something so that it would be plugged all the time. But besides that, it was pretty much what you'd expect. I can't use it for cupcakes with any kind of solid bits (fruit, chocolate chips, etc.) but I used it for a few that I made this weekend and found it worked okay. A little messy, but about 1/2 of the usual mess, so that's nice.
It did have the unfortunate effect of making chocolate look like this.
I work in a medical laboratory. I see enough of that throughout the work week! HA HA! But, after baking, they did turn out nicely.
All in all, I think it's probably worth the $4 but not much more than that. Maybe if I get into candy making or something like that, this would be more handy.