i have 2 scs 1 cervical and one lumbar there are a few very signifigant differences. 1) the crevical one is inside my spinal cord and caused mt rsd do spread. i couldnt swallow (eat) for 8 months and had to have a feeding tube and the rsd jumped into my lower body. 2) the lumbar stim is a stage 4 abs (much better quality) i had no spread problems. the stim units were attached to my nerve roots which means the unit is much more percise and much more efficient. ii only have abs systems but if you have any questions please feel free to fire away. i have experienced most of the pros and cons the scs has to offer.