The initial burst is lovely. Existence is a clean, soapy, and sparkly musk but then my nose detects something really synthetic and almost waxy. It doesn't overpower the fragrance, but it stood out in the first 10-15 minutes before it mellowed. I love it when florals are blended with ambergris. This one is done well. Yes, this is comparable to Musc Nurasana.
On my skin, I didn't get much longevity; not that I expected it to be a powerhouse. It may last a bit longer on fabrics.