To be honest, I don't think there's much of a difference between major brands, and in most applications, much of a difference between coppers and platinum.
Marketing hype...
Now I wouldn't be buying plugs from the "bargain bin" that have brand names you've never heard of... While all plug gaps will expand over time due to heat.... some cheapies can get a REALLY bad expansion...
I have over 30k miles with my blower running on Autolites, and they still look fine....
Now THAT'S not hype...

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Uncle Sam
"What the hell is up with all the gauges?
Calling Captain Kirk, your ride awaits... Phasers on stun...."