I used to break aluminium booms regularly;one a season !!! Stopped using them 5 years ago and not had any breakages since. (Use Amex Carbon Pro)
IMO carbon booms work out cheaper and make sails more stable;especially bigger ones. Give more peace of mind too. Dont think they are as light .(Amex arent anyhow)
I`ll never go back to aluminium booms. Lets face it we stopped using aluminium masts years ago ???