That’s because Compex has deeper pockets and was able to sponsor the studies. However, the protocols (programs) that were used in the studies are identical between the Compex and the Globus machines.
But the Globus machines sold in the US have a somewhat more robust (longer) pulsewidth: it increases the strength of the contraction at the same current intensity; conversely it allows to decrease current intensity to obtain the same contraction strength, thereby increasing comfort (see the relative post on Chronaxie and Rheobase and Lapique’s Law in the EMS Theory thread).