I, Jim, rarely experience backbone pain, so using the Freespine has primarily resulted in improving my flexibility and awareness at 66 years old.  What I particularly notice is that my ability to rotate my spine and look about has improved in all movement.  I tend to use the Freespine and then take a walk afterwards as this amplifies changes in my nervous system.   What the Freespine has also helped me notice (with Mercedes pointing it out) is that I tend to not let my head be released.  By letting my head and neck move more freely up-down and left-right with the rest of my body results in feeling less tension in my upper body.  
We continue to be impressed with the Freespine.  Mercedes injured L3-L4 about a year and a half ago - 5MM bulge - so she is enjoying the Freespine machine movements and they are making her feel better - less than a week using it.  Yesterday she did a 130lbs deadlift at the gym among other exercises.  Before she would tend to twist her torso to achieve moving the weight.  Now she is getting the movement from the ground  and it is going up and through her body. This is really good.
We are  confident that your invention will return Mercedes' spinal injury back to normal - and further improve the co-ordination of her torso with her legs.  I am enjoying using it, too.
I, Mercedes, really like your machine.  For the first few weeks of my using it, I got a little bored and didn’t think there was much difference from swimming.  But after some other reading online, I realized there is a huge distinction between the Freespine and swimming = gravity.  That realization (and feeling safe with the Freespine) led me to start moving on your machine a lot more laterally and vigorously. As a result it finally got fun and fruitful in stimulating my mind and body.
PS: “Here in the USA, it is interesting that when spinal surgeons injure their lower backs, they mostly opt out of having surgeries for themselves!”