I have to admit that I'm a big fan of the original film: 'The Omen' (1976). It is quite psychological and centred on the unravelling of the perfect, controlled lives of the central couple. It also touches on the hypocrisy of the apparently solid, strong central character Robert Thorn (played by Gregory Peck). As such it doesn't depend on gore or flashy effects. Many of the performances, like the Satanic Nanny, are understated but filled with menace.
This pentology is not just about the first film, however, it is pretty much exhaustive. Not only does it have the first, second and third film but the remake of the first and made for TV film, 'The Awakening'. If that is not enough you get alternate endings, a featurette on the Omen Curse, the omen music and alternative commentaries (amongst much more). If you are not an expert on 'The Omen' after watching all this then something is wrong with you.
I learned a lot by viewing the bundle. I didn't realise how comparatively small the budget was on the first movie (two and a half million US$) and how the money made had helped to finance George Lucas! The Curse or Coincidence featurette was quite scary. Sometimes I wonder if evil is just an absence of good or a positive (if that's the right word!) force in its own right. Planes getting struck by lightning, accidents during filming - it's all pretty creepy and thought provoking.
The price seems a lot to fork out but really when you consider how much material is here you are getting a pretty good deal.