Personally I am a fan of iridium plugs. I have only had one problem with platinum plugs. I put Champion platinums in my 07 Grand cherokee (wk) 5.7 hemi and they caused it to randomly stall. Found this was the cause since eventually Chrysler was contacted and the engineers spoken too. One of the times I was pulling 6k on a flat bed trailer down hill on the highway, it stalled and then since the key was on and the converter locked, started itself again with a bang and I nearly lost control. So, if you have a hemi don't use platinum plugs, lol.