TENS units have been around for decades. Every once in a while someone tries to turn it into an exercise machine, but this is mostly marketing, not anything new.
This thing is more like a modified MRI machine than a TENS device, which part of the fascinating/creepy quality for me. It's something like orders of magnitude more powerful than TENS.
It's a pulsed electromagnetic device (PEMF) and they have also been around quite ahile. While they've been show to aid bone growth and they probably help recovery in some other, subtle, ways...EMSculpt is classic snakeoil bullshit.