I got some from a breeder last year that were calm and sweet and lovely. His weren't available this year, so I tried someone else, and they are the flightiest chickens I have ever had. They are terrified of everything. They are beautiful, mind you, but scaredy! The eggs they came from were very dark. Frankly, I'd rather have calm chickens and drop back to a five or even a four on the color scale...
I think it always pays to find out not only if the breed you're getting will suit you, but also if the strain will work for your needs. If you're buying from a hatchery, even, it can help to talk to people who have purchased THAT breed from THAT hatchery before.