The penalty is the same in theory, but if you already have a dui on your record, it can backfire since it can be seen as avoiding detection due to the the subject knowing he or she is guilty. Deals worked out for avoiding jail time, reduction community service, reduction in license revocation, or getting a provisional license with the ignition interlock, can be off the table and the court and/or jury (if it goes to trial) may throw the book at you. Additionally the police can obtain a search warrant with probable cause and tie you down to a table and take a blood sample.What's the penalty? Up here the penalty is the same for refusal as it is for failing. The difference is you can go to trial and try to prove your innoncence if you refuse, but if you fail outright you're fucked because you've given them the required evidence.
Personally, I detest drunk driving, but the idea that you're required by law to provide evidence against yourself is craziness.
Side note: since the cops found the open container, I'm guessin they administered the took the breath test an hour+ later because alcohol levels rise after recent consumption. On the scene he still would have been way above the limit, but wait an hour and walla, double or double+ the legal limit.