first thing i would say, as everyone else has said, they are incredibly fast when theres food about, keep fingers, arms, legs, pet jack russells etc, well out of the way at dinner time 8)
secondly, they are strong, you'd probably have more trouble removing a 10ft boa than you would a 15ft+ burm if it got a hold of someone.
but that aside, they are generally pretty placid snakes, mine allow a certain amount of fuss to be made of them when they come out, the male more so than the female.
i dont strike feed mine anymore, they are quite happy to have the food put in and they'll eat it without the whole constricting process - which is good in my case as they're colombians so will be around the 10ft mark and pretty muscular when fully grown!