Atlas is a long lasting perfume with also good projection, but the scent may not be to everyone's liking, since it is not common... I would describe it as salty and fresh, but the salt is a little bit overwhelming at first.
I have not smelled megamare so I don't know how close this is to the Orto Parisi fragrance, but I assume megamare is stronger and a little bit different.
Get this if you want a room filler fragrance and also if you like challenging perfumes, Don't overspray it, I think 4 sprays are enough.