The dogs got a 4-ball Hyperdog slingshot/ball launcher for Christmas, so today we spent a drizzly half hour or so at the dog park trying it out. It comes with 4 tennis balls, so it's ready to go out of the box.
According to the product description, it'll launch a ball up to 220' (67m). I'm pretty sure I could have cleared the dog park from end to end with it pretty easily. Even with a short pull back you can launch the ball a good distance. Nala definitely had a good time running after the ball. Simba didn't quite figure it out yet, because all he saw were the balls in the launcher, rather than the one that was launched.
It's pretty comfortable to use, with a padded arm brace to absorb some of the pressure of pulling the ball and pouch back. The product description also boasts hands-free pickup, but this tended to be somewhat awkward because of the slingshot arms. I ended up finding it easier to just pick up the ball with my hands.
If you're squeamish about picking up dirty and slobbery balls, you'll probably want to stick with a regular Chuck-it or something similar for true hands-free play. If you have a dog that likes to run after balls and want to be able to send something far downrange, it doesn't get much better than a Hyperdog launcher. It's best in large, wide open fields and where the density of people/dogs is relatively low. Launching a ball and beaning someone in the head probably wouldn't make for a good dog park experience. It would be perfect for the dog park at James Island County Park or Palmetto Islands County Park. It'll work fine in smaller areas too, but you'll have to be careful about how far you pull back and the launch angle.
I think the next thing I'll do is replace the regular fuzzy tennis balls (hate how gooey and nasty they end up getting) with some Chuck-it rubber Ultra balls. They're a little heavier, don't get quite as dirty or gooey, and are easier to see in grass than a dirty tennis ball.