Gems is so much less problematic. No moving parts in the ignition system is a huge plus. The distributors have so many issues like water under the cap, modules and coils. The whole issue with the module getting too hot in its original location and being relocated to the bracket the coil rides on. Then I learned the hard way that the module takes the coil out. I learned that by replacing the module(no correction) took the module back out of the car and reinstalled the original then put a coil in it(no correction) left the coil in in and went back to parts for the module and installed it again with the new coil still in(fixed) So after going thru all that shittery once, I learned and used to put the coil AND the module in.
If I ever started going down that rabbit hole I'd just replace everything with the DUI HEI.