Dual-point vs. Single-point distributors - pros and cons?

The GM HEI ign is the way to go & simply hard to beat: cheap, reliable, minimal electrical connections [failure areas ], high spark energy [ 0.060" plug gaps].
The magnetic p/up type ign systems do retard slightly at higher rpms due to distortion of the AC output from the pick up [ explained in the link I posted in post #11].