There is really nothing bad wiht hydrallic systems chevy has used it in their v8s for years, and still does to this day. Maybe ford is changing it as an experiment, maybe for other reasons, only thing with hydrallic lifters is that if the engine is run low on oil, so there isn't enough oil pressure to fill them, you can collapse the lifters. I don't know much but I do remember this from auto tech last year....anyways hope the information helps out at least some.
