Ambrostar is ambrocenide but better. It's also a misnomer - not a star as such, but a veritable black dwarf floating out there in space. Dark, woody, ambery, but also somehow glinting. Perfect for oud compositions but also for boosting and adding intrigue to just about any accord. 
 
The claims about it being 20X stronger are a bit overstated, but it's approaching an order of magnitude for sure. 
The longevity is fascinatingly eternal. 
For now, I advise starting with the 10% solution - see this as a set of training wheels so you can best compare to Ambrocenide, which also tends to get supplied at 10%. 
Genuine stock of this material is a bit hard to come by, but this is actual direct-from-Symrise stuff. 
01/09/25 Update - more stock secured, so I am adding the option to buy neat too!