I think it's adorable and fresh. It's used far less than Joey, which is getting kind of old. It's also a safer bet than Job if you don't like the religious connections, or the chance of it getting mispronounced. Joby is a winner!
My name is Joby and I was actually named after the professional hockey player Joby Messier. When I was a baby, he actually held me for a picture and my parents told him about the name. I've only known of one other Joby, who climbed Mountain Everest to wingsuit jump.