I was changing the plugs on my'41 Ford PU and it hit me that I was not using the rule of thumb my older brother taught me decades ago about using Motorcraft in Fords , AC's in GM's Bosch in European cars etc. I've had some problems with Champions fouling (years ago) but not much else in the way of issues that I tied to a brand. I suspect many of you have strong opinions about specific brands. Does brand matter much to you or do you just buy the one on sale or what? Is there much difference between brands in your experience?