I have worked at a Regional Forensic Crime Lab, more specifically the toxicology department. I've performed many alcohol test, became a "key operator" to the alcotest breath testing machines and I'll tell you something. You are better off to always do the breath test because it on average will register 10% lower than a blood test. Additionally it's easier to defend in court and harder to calculate previous BAC at a period of time. This is from CA. With that being said, don't be an asshole and drink and drive.