Mainly, it seemed the most likely candidate to receive an unlocked boot loader and have developer support on Verizon. The crazy screen, slim bezels, micro-SD card slot, removable battery, laser auto-focus, button layout and $99 on Verizon deal didn't hurt. Gotta say I love the double tap screen on/off feature. Aside from that, I don't like the looks of the S5 or its health/finger reader gimmicks (not going for the company that developed KNOX either). The m8 is heavy, slippery, and more fragile due to its metal construction, not to mention having to deal with S-off BS, etc.
The Note 4 would probably be tempting when it comes out if the boot loader does not actually get unlocked, though the G3 is still very useable one handed. LG makes very nice cases to add protection, wireless charging, and not increase thickness hardly at all.
Here is a gallery of the setup. I had to reduce the screenshots to a quarter of their size to avoid the 2560 x 1440 resolution.