POSITIVES: 1) Many programs, both for pain treatment (TENS) and for muscle training and aesthetic improvement (EMS) 2) Sturdy machine, quite powerful in the intensity of the currents and the battery lasts a long time. 3) Can be used by professionals as well. 4) Very detailed instruction booklet (although the specific device I purchased did not have Greek) and another for the correct placement of the electrodes. 5) Very good quality of the provided adhesive electrodes. 6) Quite long cable length - can be comfortably used by tall people - and with good insulation. 7) Comes with four additional cables - splitters that allow for applications of a total of eight electrodes. Effective for sciatica and other pain cases, but of course requires systematic use, at least 8 to 12 times, to see long-term results and always in combination with some heating/pain relief cream or some NSAID, etc. (Electrostimulation simply makes the pain less noticeable, it does not heal the problem on its own!) You will have temporary relief from the very first use.
I cannot comment on its durability over time, as I have not had it for long. Also, I have not extensively used the muscle training functions (EMS) since it was mainly purchased for pain treatment.
NEGATIVES: 1) It does not have a keyboard lock, so if the ON/OFF button is accidentally pressed, it will turn off and you will have to start the program again. However, so far this has not happened to me. 2) The cables are long and well insulated as mentioned, but at the same time, this makes them somewhat awkward. 3) Navigation from program to program only goes upwards, so if you want to go from TENS #5 to TENS #2, you have to press the button 17 times. However, if you change the mode from the menu, it will take you back to #1. 4) There is no option for user-customized programs. (....Although you probably won't need something like that).
OVERALL: A good, reliable electrotherapy device that could certainly be better!