Many years ago, an 'old school' car mechanic (i.e. one who knew a thing or two, not just having factory certs on how to plug test gear in!!) told me to use NGK plugs. When I asked why, he simply said lots of ignition related faults could be cured simply by swapping Champion plugs for NGK ones, even if the Champion ones were new.
Now, I don't want to knock the quality of Champion products, and I use their oil filters with no probs. But I always use NGKs and change them regularly and I have never had a plug problem...