Here's a link to MSD's "Ready to Run" distributors:
https://www.holley.com/brands/msd/pr..._distributors/
My experience is with a pro billet distributor and an ignition control box with an external coil. The box sends 4 sparks below 3,000 rpm, and a longer stronger spark above that. It makes sure to get a complete power stroke. That set up went over 100,000 miles in a 6 year period. A few of those years were 25,000 miles per year with heavy interstate hauling. It was always turn key to start, and never left me anywhere.
I can't remember if I experienced a miss or I was inspecting the distributor between engine builds, but the shaft was loose. MSD had a service to install new bushings, drive gear, and any other wear items for a reasonable price. What I was told is that sometimes there is poor oiling to the drive gear. I would buy from MSD again. I believe that the GM HEI modules are susceptible to heat, and I had one with loose bushings also. So it happens.