Deontologist ethics are preferable to utilitarian ethics
You can judge an ethic only on its outcomes. Deontologist ethics are based on simple principle that protect us from bad outcome in most case. Utilitarian ethics are a bit more sophisticated and aim at giving the best outcome possible "in average".
Utilitarianism could lead to absurd and subjectively unjust consequences. If, for example, I am more skilled in managing money then you are, utilitarianism can be used to justify that I expropriate the content of your wallet or bank account.
Utility cannot be measured adequately. A utilitarian cannot say with absolute certainty that taxation (expropriating a person's (usually) money for the benefit of government agents) is justifiable whereas a deontologist can say with absolute certainty that property is absolute and theft is immoral.