One of the major difference is that 99% of the machines made have coil cores made of 1018 cold rolled steel. Mine are made of pure iron, which is not only extremely difficult to find but also extremely expensive. In most solenoids 1018 is fine, but here pure makes a difference. You want the magnetic field to charge and dissipate as quickly and cleanly as possible, with the lowest magnetic reluctance, and for the core material to not become permanently magnetized during it's use.
My goal was to make a machine that looks pretty AND runs well (consistent force output over time, easily adjustable to perform specific functions, and doesn't get hot during long periods of use) and makes tattooing just a little bit less of a chore.
I'm not going to get into specifics beyond that. Trade secrets and all that.