I would guess the reason it costs more is that OS probably has a more costly operation to begin with. Then they have a reputation so the engine is going to be well made throughout and it will be backed and supported properly. And finally they get a premium for who they are.
I don't know enough about the engineering of engines to have an opinion but I think the biggest obstacle to overcome is the weight of an ignition. The electronic ignition took away a lot of that weight while the module gives a percentage of it back.