I agree on the Russian stim. It’s old technology, completely surpassed by square-Wave technology.
I tend to disagree on the fact that the 4000R is a good machine: pulsewidth is key. The 4000R goes up to only 300 microseconds in pulsewidth, which is definitely suboptimal or insufficient for large muscles like the quads. If you read the EMS Theory thread there is a section explaining how pulsewidth affects contraction. Anybody who has tried a Compex (400 microseconds) can tell you the difference. And people who have compared the Compex to the Globus (450 microseconds), can tell you that the stimulation feels even a little bit more energetic and comfortable. Also read this post from a user who switched from a generic machine to a Globus.