Of the three batteries, JumpStart Flip does the best job of combining the right features, pricing, and design to evolve the traditional high-capacity USB battery pack into something smarter and better. The roughly iPhone-sized battery pack attractively blends chrome metal and black plastics to create a flip-open video stand, using a sheet of passively grippy rubber to hold the iPhone or iPod on its face. So long as the back of the Apple device or…
