I've seen Atlas. It is gorgeous. It would have been my choice had I not decided to stump up the extra money for Slate Grey. Atlas is a great mix between dark blue and dark grey. Very understated and sophisticated IMO. The car I saw it on had a sand beige interior and looked the dog's.
It doesn't look light at all - you maybe run the risk of it just looking like dark grey in the wrong light, but I wouldn't worry about it looking too blue or light, it's a very deep, rich colour.