We've had it in Arizona since 2010. When it was signed into law, a local newspaper columnist wrote a "doom and gloom" hit piece on it, predicting the inevitable anarchy and bloodbath. 18 months later (to his credit) he penned what basically amounted to a retraction. The sky didn't fall. People still did stupid things but no more than usual.

Also, Arizona retained it's permit system and recommended that people take the class and get the permit anyway, which I did. The Arizona permit is honored in just about all western states except for the 3 Pacific coast states. No comment on that.