Hall effect triggers are perfectly accurate. The problem with Pertronix is the distributor itself is usually inaccurate COMBINED with shoddy electronics that only make it worse.
A crank trigger is the most accurate: there is no slop there. Add up the backlash of every gear/interface though: to first the camshaft, then to the distributor drive, then between the drive and the distributor, then to the distributor itself. The slop all adds up.
The original Pertronix I had in the 80s in my Scirocco was absolutely flawless. Such as it is with the ever decreasing quality of merchandise today, and we all know where it's made.