I got burned on using some Denso Iridium Power plugs for my van. After 35,000 miles, 3 out 6 plugs were down to the nub---the iridium tip was completely gone. The gap was maybe double what it was supposed to be. Van started running poorly was how I found out.
I preferred Denso and NGK before this experience. I replaced the bad Denso plugs with Autolite Double Platinum---van now runs great.
I'll probably go with Autolite moving forward, as I cannot tell a difference between new plugs, and it seems like it is too risky to install Denso or NGK, what with so many counterfeits out there. Changing the plugs on this van was a huge pain. I don't want to have to do it again.