The two I know are polar opposites in terms of their appeal:
Amouage Gold features a strong central civet note, wrapped in honeyed florals that leave the whole thing smelling like syrupy urine on my skin. Why would I pay $200 for this when I could pee in my pants? (I have no problem with civet in general, but I think it's handled very clumsily here.)
Others have experienced Gold quite differently, I must admit.
Then there's Dia - one of the most enchanting fragrances I've ever worn, and worth every single dollar I paid for it. Floral notes ensconced in frankincense and Cistus ladanifera, underscored by precious woods, spices, and the softest leather you can imagine. It transforms and develops continuously as I wear it, and to my nose it's beautiful at every stage.
I've never bothered trying Ciel, Silver, or Arcus, having decided to leave well enough alone after discovering Dia.
Most of the Amouage scents, especially Gold and Dia, are reviewed in depth here on Basenotes, and I'd suggest some browsing and some testing before making any decisions!