I have an Action 1MD. It''s a single diaphram pressure plate with an unsprung 6-puck disc with Miba friction pads. Before I bled my clutch, it would engage kind a high, and I wasn't used to it, so it would chatter if I wasn't paying attention. After I bled the clutch, it drives pretty much like my stock clutch did, and it only chatters if I seriously under-rev it, or am late with the clutch during shifts. The light weight of the unsprung 6-puck disc makes for nice shifting and engagement. I can't really say anything about ACT discs, but I like my Action. I do have an ACT Street Lite flywheel though, very nice piece at a very low price.