Noted YouTube guy and occasional Android Police guest, MKBHD got his hands on an LG G Flex from South Korea and as is his custom, has made a video about it. If you've been wondering about that self-healing back, this video will clear some things up for you.
LG went to great pains to show off the scratch-resistant back material in a recent video, and it was pretty impressive. As MKBHD points out, though, that was shot under ideal conditions. The wire brush used made a cluster of very light, but easy to spot scratches. A deeper, more jagged scratch from your keys might not heal as well. On MKB's test device, scratches from keys healed fairly well, but a deeper slice with a knife never went away completely.
Also of note, the ambient temperature affects how fast the material heals. The original LG video was filmed in a warm room – about 81 degrees F. In a colder environment, it takes longer for scratches to fill in. LG didn't use any trickery to show off the flexing part of the G Flex, though. MKBHD flattened it out with his full weight and the device continued to work fine.
The G Flex packs a 6-inch 720p curved AMOLED screen, 2GB of RAM, a 3500mAh battery, Snapdragon 800, 13MP camera, and 32GB of storage (with no SD card). If you're salivating over this phone, there's a full unboxing video to watch below. Keep in mind these are Korean devices and there's no official word on bringing the device to the US, though @evleaks says it's happening.