What it makes micron is air nozzle and very small distance between paint and air nozzle they make, that's why microns can work at low pressure. Compare Eclipse and Micron for that. Just my opinion. SP series has air nozzle like micron series, so it's not strange they'd spray the same.
I made models in my childhood, but I didn't know what the airbrush is then
If I'd do modelling today, I'd definitely buy CM-SB as you can spray at any angle and you can get the smoothest transitions and details with it, actually none of my ABs can produce such a fine spray as microns.