We have a 2-3 man tube and rarely gets used. Good for a nice quiet pull, and very difficult to tip over, so very safe. I find it must travel at higher speeds to get any skipping.
Now for good fun, we always pull 2 separate donuts. Sitting in the hole it's very stable. Lying on your stomach, it's gets very tippy and really skips.. And that's going in that 20mph range. If you drive nicely, they will tag each other from time to time. A little more input from the boat driver, and you can get all kinds of action from the tubes going back and forth. Get a good zigzag rhythm going and everyone loves the ride.
Some people say its way too dangerous, but a little common sense and the driver controls how the tubes go back and forth and if you want a big collision. Us big adult kids usually fell off from laughing too hard.