Reliability and consistency is what you want from a spark plug that, after all, lives in a fiery he11-hole of a home only to ignite an air-fuel mixture. I will take a good NGK plug any day over a Flux Capacitor Plug and Super Swirly Intake device.
Pulstar vs NGK Iridium IX vs Denso Iridium --
Sparkplugs.com - Spark Plug 411