Posted by Greg Wilson on 2009/09/22
Few topics in programming generate as much argument and as little value as wrangles over where the curly braces should go in C programs, or whether CamelCaseNames or pothole_case_names are better . That said, consistency definitely matters—plenty of studies have shown that MiXiNg styles disrupts comprehension—so having a style guide and sticking to it is more important than what the style guide actually says.
I’m therefore grateful that Google has started posting its style guides for all to read. If your project doesn’t already have one, and you’re using a platform Google cares about, adopting theirs is probably the least painful way possible to solve one of the many startup challenges you face.
 Short answer: a study in the late 1970s seemed to show that pothole_case was slightly more readable for people who’d learned English as a second language, but both the effect and the sample size were too small to be reliable.