There is one odd note, though. Trianium left a gaping oval opening that reveals the iPhone's back and accentuates just how thick the case is. It's meant to give the camera some breathing room, but the look is jarring. It isn't a deal breaker at all, but it definitely looks a little funky and I'm not particularly fond of it.
The Atomic S charges through a Micro-USB port. Because the iPhone uses an eight-pin Lightning Port connector, you may have to carry two cords around -- it's annoying, but pretty standard as far as these charging cases go. However, if you keep your iPhone in the case and plug the case into an outlet, you can juice up both devices that way. (Another choice would be Apple's Smart Battery Case, which uses Apple's proprietary eight-pin port, too.) You'll also get a headphone extender since the thickness of the case prevents some headphones from reaching the handset's headphone jack (another typical add-on).
With its beefy battery capacity, clean design and competitive price tag, Trianium's Atomic S Battery Case stands out from most of the other cases I've seen. It's a lot cheaper than Mophie's case (though it has a smaller battery) and better looking than Incipio's Offgrid Express; and its indicator lights don't work as annoyingly as those of Anker's Ultra-Slim Battery Case. So you want a battery case for your iPhone at a reasonable price and aren't looking for any special features, this one should be your pick.