It seems all todays saws use NGK plugs. I've found a few duds with these plugs.
I always had good experiences with Bosch plugs [made in Germany]. The only problem they give like any other brand is after a while the gap in the electrode spreads, goes from .020 to .030 and the saw won't idle. I pull the plug out, stick a doubled up match book cover in the gap and tap the end with my scrench to tighten it up.
Good to go again.