An up-front payment of $600 nets you the 16GB black version of the S5, which has the same 16-megapixel camera and speed-demon quad-core processor as the standard version. What's different, then?
Most importantly for developers, this version lets you forget about Verizon's bootloader and play around with custom firmware.
Of course, the desire to unlock or even completely do away with the boatloader isn't limited to developers -- Verizon will happily take your greenbacks even if all you want is a little more control over your preloaded OS.
Read up on all the pros and cons of this phone in.