If you're familiar with YSL, you probably noticed first thing that the cap is missing from this polish. This was the way it came to me; however, it came from my sister, who works at an upscale department store, so I have no doubt about its provenance. It's very pretty, and it's something I never would have bought for myself, not at that price ($28, according to the link below). The only reason the cap might particularly matter to me was if I intended to re-sell it, and I don't.
Bleu Cobalt is a current color. Ninja-licious was an LE polish and if it's on Pretty Serious' website I don't see it. (Damn, I shouldn't have looked. I haven't bought any polish since my birthday, two months ago, and I see some new polish in my future.) (This is what I'm looking at. Currently on pre-sale. For one thing, the names! but also the polishes.)
(added: Here's Ninja-licious on PS's blog - only 300 units made, wow. **Also possibly I've been spelling it all wrong - they say Ninja-Lish-ious, presumably because it's in honor of their US shipper, who is named Alicia. I have it spelled right on my spreadsheet and it looks like on the wheel, too, but slipped up when I first wrote this entry. I fixed it at the top but I'm not going back right now and fix every misspelling!) (I also spelled Bleu Cobalt wrong in the title so I'm 0/2 on spelling in this entry!)