Juror doubts alone won't warrant a mistrial - however all the errors (Judge Colbath I want a refund on my tax dollars for your evident bias/not moving this out of palm beach etc) cumulatively an appellate court will find tainted the trial environment to the point it may have influenced the verdict. I think they still would have found him guilty of something (probably vehicular manslaughter) but all counts based on the evidence presented (and the way it was presented) - don't think the jury necessarily ever factored in 'reasonable doubt'.
If St. John had stuck with "not guilty" it would have been a hung jury and guess what - we would still be having a retrial. Only in that case Goodman would not be in prison pending the retrial because he would not have been convicted. All of you who are so vehemently against Goodman should thank St. John for getting Goodman to spend time in jail. Leave the poor man alone, he doesn't want fame or fortune and is just trying to be honest.