That article is bullshit. Just because Mr. Putman can't tweak a needle valve to fix a hesitation anymore doesn't mean that the auto makers are hiding their evil secrets from the poor, innocent independent repair shops. All you need is a scanner and the proper software cards. Snap On sells them, and if you update your software yearly, there will never be a problem.
My advice to anyone that comes up against this while working on a car is this: Get with the program. This isn't the '60's. You need a computer to fix modern cars. Buy one or go work at a dealer.
Magnetos use the rotational timing of the engine and crank itself to switch power from a coil to the sparkplug. Magnetos are very reliable, but most aren't adjustable (for advance and the such). Magnetos also produce a very powerful arc that interferes with radio and just about all transmitting electronics. No one around you can hear radio, talk on the phone, etc.
For planes this isn't a problem. The Arc is far below the amplitude of FCC radio frequencies, and the reliability of it outweighs the problems. Also, lots of airplane ignitions have individual coils just before each sparkplug. That means that the RF bleed is rampant.