I have always gotten better performance from a new set of plugs, irregardless of brand or style, when I replaced my old plugs. Otherwise, I have never really seen a difference to the plus side of any plugs, but I have seen some differences to the negative when it comes to multiple electrode plugs. It seems to me that the spark has to search for the "sweet" spot in order to fire. I have found it best to just use a good plug (like AC, Autolite or Champion) and index them.
As to comparing various spark plugs, this would be a great test on a Dyno, if anyone had one. I would like to see the results of all plugs when they are put to the test head to head.
2015 Cherokee Trailhawk V6.