I went with the ngk iridium as they were on sale. I doubt I see any difference, but I thought I would give them a try. Hype or not, there weren't any negatives, so really no down side since they were the same price. I have used ngk on my bikes for years and have loved them.
I too recommend pulling plugs occasionally to see whats happening. Its the closest thing to a window your engine has. I stuck my milwaukee snake light camera in the holes for two reasons, first to see If anything looked wrong, second, to justify my purchase of a snake cam
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Take it for what its worth(marketing), but still has some merit.
Q. What makes Iridium better?
A. Until recently, platinum was considered the best material to use on the top of an electrode because of its durability. However, Iridium is 6 times harder, 8 times stronger, and has a melting point 1200 degrees higher than platinum. Put that into a harsh environment such as an engine piston chamber, and you have a spark plug that can resist wear much better than platinum. Additionally, the DENSO Iridium Power alloy is so durable; it allowed our engineers to produce the world’s smallest center electrode (.4mm) which reduces the voltage requirements, concentrating its sparking power. Also, its smaller size, combined with the tapered U-Groove ground electrode, allows more room for the flame kernel to develop and produce a more efficient combustion.
Here is some propaganda..
http://www.spark-plugs.co.uk/pages/technical/iridium_spark_plugs.htm
OMG you gotta read this cheesey write up... "it comes form asteroids that killed the dinosaurs..."
http://www.densoiridium.com/faq.php