EDM lifters,supply the cam/lifter mating point,with consistent cushion of oil. Normally splash oil lubricated,these work great on the street. FWIW,seen two sets installed personally. With today's cam problems,extra insurance never hurts anymore.
The EDM hole is the center of the lifter and that never contacts the lobe. They hit the area with a "directed splash" - they do not pressurize and support loads on the mating surfaces as the oil film on the bearing does for the crank.
IMO - if you have a very high rate of lift cam (custom .904 only lifter type deal), heavier valve springs (more than 400lbs over the nose), or have a moderately big cam and expect to have a lot of idle time and possible issues getting the engine to fire right up - then they are good insurance.
