The real issue here is do I want to provide evidence for the prosecution of my case.
If you are so drunk that you cannot stand up and are slurring as you talk then whether or not you take the Breath Test is of little consequence and you may as well take it and not incur the 6 month loss of license for refusal. However, if you are borderline, aware and alert enough to think this through, then by all means think about the following.
You cannot be forced to incriminate yourself.
If you refuse to take the Breath Test, this cannot be used against you. In fact, at trial, the prosecution cannot even mention that you were offered test. They can talk about the other things that you did do, but they cannot mention that you were offered the test and refused.
But what about the 6 month loss of license?
If refuse to take the test and lose your license for 6 months but win at trial sooner, there is a presumption that the court will order your license reinstated. That means that if you deny the prosecution this critical piece of evidence by refusing the Breath Test, and therefore get a Not Guilty verdict, your lawyer can ask the judge to reinstate your license after trial.
How do I know that I will win at trial?
You don't. However, if you were borderline and did ok on the field sobriety tests (9 step walk and turn and the one legged stand), these and a few other pieces of opinion evidence, which should be aggressively challenged by your experienced defense attorney, will be the only evidence against you. While there is never a guarantee, your chances of success at trial skyrocket under these circumstances.
A last thought for analysis.
There is no universal right answer to whether or not to take the Breath Test. However, if you are slightly under the influence and think that you passed or did pretty well on the other tests provided, do not let the Breath Test be the death blow that sinks you.