Well I wasn't trying to say that everyone would have these results, that just been my experience.
No problem, got that from the get go:).
Yep, Platinums are good (as long as they aren't Bosch!) and Iridiums are better, either in NGK or Denso. Typically the Denso plugs are 50% more in cost, so go with NGK. We never put Bosch stuff on any of the cars at the shop due to such high failure rate of parts. Our Techs won't even put the stuff on. Just our experience.
Bosch is a very old German company. They have produced extraordinary stuff since forever. So I must ask, do you have an example of any such failure personally? Mind you, I have no problem with NGK.