No not really a Chevy or Ford argument. It is a known fact that:
The TFI coil puts out 1-1/2 more than a HEI coil = Better spark
The DS system has a ignition spark retard to help start a hot engine or a high performance engine, HEI does not.
If you don't like the DS box, you can run a GM module in it's place with the TFI coil.
The biggest draw back to the GM HEI is the coil in the cap, and the module in the cap design. Coil in the cap means that all of the Radio Frequency Interference, and Electro-Magnetic Interference that the coil produces (and believe me, they are REALLY cranking out the 'noise'!!) is directed at the module and the pick up trigger coil...
(Ford fixed this by moving the module and coil to different locations.)
On the HEI, the high voltage from the secondary side of the ignition passes within 1 1/2 inch of the module!! One ground fire to the module, and you walk! When the high voltage escapes to ground inside the distributor, (That's when, not if...) you are guaranteed a false firing of the Hall Effect trigger.
(Ford fixed this by using a much taller rotor, and shielding the Hall Effect trigger.)
The center electrode (Button) is normally a soft, relatively high resistance graphite. This graphite comes off when the voltage is passed through it, and when the electrode comes into contact with the moving rotor, and small amounts of CONDUCTIVE graphite are distributed all over the inside of the cap and on the rotor, causing the high voltage to follow it, instead of going to the spark plug terminal like it's supposed to. If you see black dust in the cap, or on your rotor, you have the problem.
(Ford uses a much harder, and lower resistance center electrode to correct this problem.)
With the short rotor barely covering the internal centrifugal advance mechanism, you are guaranteed to get lots of firings to ground, both around, and through the rotor. (Look for 'Red Dust' inside your cap and rotor. That is the residue of extreme heat 'welding' the advance weights to the pivot pins from ground firing.) (Ford Solved this problem by using a much taller rotor, physically putting distance between the distributor internals and the high voltage.)
The HEI distributor cap is non-vented, so the high energy discharges build up ionized air, called Ozone. This ozone promotes ground fires, cross fires and chain fires inside the cap, further adding to the confusion...
(Ford fixed this by venting the distributor housings, and in some cases, the caps themselves. Also, Ford uses vanes in the cap to stir up the air and keep the ozone from collecting in the top of the cap.)
And the list goes on.
GM could never design out all of the defects, so the entire Coil-In-Cap design was scrapped. GM now uses an ignition very similar to the Ford ignitions. Just do a search.
The GM HEI's good points are...
--With the one piece cap with no vent, the cap works as an air bubble to keep the high voltage circuit moisture free when driving through water.
--The GM HEI is a one piece changeover, meaning if you have to change distributors, it's loosen one bolt, pull a couple or three wires, and change the distributor.
--There are parts for them at every discount auto parts store, and most farm implement stores in the country (and abroad for that matter)...
--They are EVERYWHERE in junk yards for cheap...
--A fresh Reman with core charge at the discount parts store is under $125.
90 YJ, 4.2 with 2150 carb 4.0 Head and headers, Nutter with TFI and MSD. 1" BL, 2.5" spring lift, 33", Goodrich KM Mud Tires. Dana 30 w Aussie, Ford 8.8 w LS. 9000lb HF Winch.