what spark plugs for a mild built 340

I run NGK's, never had any issues. I'm sure running wise you wouldn't see any diff. between brands. I just think the machining, etc. seems better on the NGK's. I have pulled brand new plugs out of the box with galled threads, crooked electrodes, etc. I work retail and wholesale auto parts so I see a ton of sparks plugs every day. JMO.