What would you do in the following situation?

A friend of mine started a new job and has been working in the job for 5 months.  He negotiated a sign on bonus where the terms are that in order to keep the bonus, he needs to stay in the new job for 1 year, otherwise he must repay the bonus.  Recently he was offered another job for a better salary and bonus and more interesting work.  Should he take the new job or fulfill the 1 year employment agreement?