From Longman Dictionary of Contemporary Englishvote something a success/the best etcvote something a success/the best etcBritish EnglishTHINK/HAVE THE OPINION THAT if people vote something a success etc, they all agree that it is a success The evening was voted a great success. → vote
Examples from the Corpus
vote something a success/the best etc• But they will be in costume, and all party goers will have a chance to vote on the best disguise.• They also voted the Cappuccino the best sub-£20,000 sports car in the show. 