Last time, only time, I ever used Bosch Platinums was in the late 80's, in my 64 300's mild 413.

One of the 8 plugs lost all it's porcelain on the engine side of the plug, caused preignition.

Not interested in spending any more money on finding out if Bosch got their act together when I have had zero problems with Champions, Autolites, AC's even Motorcraft lugs.

I've used other brand's platinum plugs without failure but I have also come to the conclusion that platinum plugs really aren't my thing either. I don't own anything that would make platinum's extended change interval attractive to me and as often as I pull and inspect my plugs I'd rather just replace them as needed.

JMHO