My wife and I have both suffered with back problems and occasional bouts of sciatica for a number of years. This particular model is capable of reaching down to the lower vertebrae and can be focused on massaging the precise point of discomfort. It is also very useful in relieving tension in the shoulder muscles and can be easily adjusted to concentrate on muscle knots that one may have (and not even be aware of!). The full range of shiatsu massage runs from the very lowest vertebrae all the way up to the shoulders. It also has a roller massage option for the lower/middle back but neither of us have found this function to be of value, although others may have differing views.
I have read elsewhere that the massager is too aggressive. We have found that simply by moving one's back in or out on the seat cushion can easily achieve a comfortable roller pressure. We have also found that the heat option offers a pleasant, soothing sensation.
As this isn't a small, lighweight item, we keep the massager permanently set-up on a dining room chair adjacent to power socket.
Whilst not silent in operation, it certainly insn't obtrusive. We have directly compared this device to one of the hand-held kneeder/masssagers available elsewhere on Amazon and found it significantly quieter.
A final note but worthy of mention is that both of us have noticed that, immediately after using the massager, we feel a lot more supple and generally alert. This could explain why the instructions recommend that it is should not be used immediately before going to bed.
All in all, we find this is a genuine therapeutic aid and we would certainly recommend it to anyone with back problems, but I suggest that one seeks medical advice beforehand.