Lunati Retrofit Hydraulic Roller

Don't understand the problem it seems like a lot of you have with the hydraulic roller lifters all Magnum engines have Factory hydraulic roller lifters all LS have Factory hydraulic roller lifters all new model hemis have Factory hydraulic roller lifters they have very few problems with them I just don't see what what the problem would be with a retrofit unless there cheap Chinese knock-offs buy Mopar performance would be my suggestion