Is there a problem with platinums in the '94 5.8L?

Motorcraft lists an alternative Platinum plug (ASF32PF4) for my '94 E150 5.8L. A couple of people have told me that they have had problems running platinum plugs in these engines. Can anyone here comment one way or another on this issue? What causes platinums to not run well in an engine?
TIA,
-cadjak