People that still run magnetic ballasts are a prefect example of how many people in the growing weed business just listen to other people and can't actually review the information and make their own decisions.
It's an absolute no brained really. More light, less draw, way less heat, no sound and zero degradation over time.
One thing the old coil and core users have is low thd, even the cheapest magnetics have low thd. All digital ballast will have differing amounts of thd.
THD affects the quality of light produced, low thd , no flicker.
Lumatek at one time had over 300% THD according to one company that makes lamps and ballasts ( with almost zero thd).
Lumatek no longer certifies with this lamp/ballast company because well, who wants someone talking about their ballast and how it's thd is insane?
What digitals have is high frequency. Coil and core operate at 60 hertz, digitals up to 67 khz, the higher the frequency the better quality of light produced.