Don't be fooled by anything other than the first video, which looks pretty decent I might add (not for $400 though). The other videos play back the example in slow motion, which inherently gives the perception of smoother motion without even adding stabilization. It's an old trick, shoot HFR and playback will appear smoother. The latter examples are dishonest.
Something like http://steadxp.com/ looks much more interesting to me and seemingly worth the investment. Also, the examples are much more honest.
I have the iteration before (CAME 7500). Really a helpful piece of kit. If you operate it well (bent knees, strong core, shock-absorbing arms) you can get incredible results. All the motion shots in my reel were made with the 7500: https://vimeo.com/110867070