External batteries can be ugly and stupidly large when compared to their capacity.
The Astro Mini isn't like that at all, it's extremely portable and pocketable, as the supplied mini travel bag for it proves. It does look pretty awesome, too, and that's obviously an important feature in a battery. Going on about the form of it a little longer, it feels really solid and the metal construction is stunning.
At 3000mAh, it is able to give a full charge and then some to most devices, perfect for a night on the go, or for those of us suffering from mid-day battery death.
As for value, it's the real deal. It's a solid product which serves its purpose well and I'd recommend it if you're looking for that little extra oomph.