I personally use a champion cj8 as my general purpose plug across the board from my mower, tiller I used to own and my trimmer. Never had a prob works pretty good
I agree. I think the electrodes tend to get clogged with carbon deposits. I have had two encounters with this plug. The first is on a backpack blower, where it had failed and needed replacement. The second was on a lawn mower, and the electrodes were clogged with carbon.
That said, I don't think that aftermarket plugs are a problem as long as they have the standard electrode design.