I recently purchased the Cobalt Blue 3DS that was released 3 months ago. Not to be confused with the Aqua Blue which was a launch color for the system. This was the type Blue I wanted anyway, since Aqua Blue seemed too green for me.
This Blue has a very nice shading for it, it may one of the best kinds of Blue models since the DS, if not the best compared to those. It's definitely great up in person, and I'm actually glad that I waited for getting a Blue colored one. I'll have to get a shot of them all in comparison in a later update in this post once my 3DS is done charging. It's definitely cool stuff, especially if you have a 3DS that's American and has a different color than this. And if you're wanting to play a 3DS game that's only Japanese Region, not to mention there's a lot of other content that's that's exclusive for the region.