This is going to come up, so let's revisit my list of Greatest Quarterbacks of All Time:
1. Johnny Unitas -- overcame being cut by the worst franchise in the league to invent the modern quarterback position; won three championships.
2. Joe Montana -- reinvented the modern quarterback position; won four championships, threw zero interceptions in four Super Bowl appearances.
3. Bart Starr -- undisputed leader of the offense of the greatest coach of all time; won five championships in a seven-year span, including three in a row; .900 playoff winning percentage; highest playoff passer rating in NFL history; called his own plays and was considered to be among the best play-callers ever; led the greatest drive in the greatest game ever.
After those three, it doesn't matter.