It didn't take me long to get the hang of the Stem Gem Strawberry Huller, and once I did, I was able remove the stem and core of strawberries much faster than I could with a knife.
To use it, you push the button on the back to extend the retractable Alien-esque jaws. The deeper you push the button, the more the jaws open. Then, plunge the jaws into the strawberry, twist, then pull. There you go, a cleanly cored berry.