I personally would put the HIFU technology (be it Ultraformer or Ultherapy or other HIFU machines) together.
What I would advise my patient is that if there is significant sagging and laxity for a quick lifting effect, threadlift would be faster, albeit limited in its skin changing properties. Some practitioners would say that the PDO or PCL stimulates collagen etc, but if I consider the area affected by the threads to be minimal.
As such, I would still advise my patients to do HIFU in addition to threadlifts as there is an overall improvement of the skin laxity AND contouring due to the large areas affected by the treatment.