The Amouage scents are fairly complex, and all have some frankincense in the base. Most of them also have rockrose (or gum cistus, or labdanum), which is the base of many amber scents. They are also fairly floral for men's fragrances. (Though the complexity masks this to a degree.)
On the whole, I would say they are elegant, oriental, rich. And expensive. Guy Robert developed them for Amouage, which is a company based in the Sultanate of Oman, in the Arabian peninsula. They obviously reflect an Arabian idea of what is elegant on a man; that's rather different in some ways from our usual Eurocentric conceptions. Exotic, yet strangely familiar.
Johnson's baby powder, btw, is largely scented with Siam benzoin, an incense resin which is not too much like the frankincense that the Amouage collection all have in common. That said, some of the Amouage line do have benzoin in the base.
My impression: I like them. I own Dia and Gold for Men, and Silver Cologne for Men (which has a prominent rose note).
Definitely worth a sniff. Nordstrom has them in San Francisco. Is there a Nordstrom near you? You'd better like them a lot to shell out between $150-265 per 50 ml. bottle, though!