They say that a change is as good as a rest, and if you're getting bored of looking at the same interface on your mobile phone all the time then you may want to think about installing this theme.
No surprises for guessing the predominant colors of the Black & Blue theme, but there's more to this theme than a couple of shades. True, the color scheme does work well, and gives off a cool, slightly industrial aura. But, this theme also changes your icons, menu styles, fonts and analog homescreen clock.
On the whole, I like the design. The rounded Mac OS-like icons are gorgeous, the background is simple yet stylish and shiny clock is a nice addition. I wasn't sure about the use of Comic Sans as the system font though, and felt it wasn't quite in keeping with the rest of the design elements.
Nevertheless, Black & Blue theme provides a nice way of freshening up your phone's display.