i think bitcoin it's safe but,we must be careful because some people have a high skill to steal your coin. but don't worry about that, i think the security system in bitcoin is safe 
If you are holding your bitcoin in online wallet or in an exchange then it is not safe, and at any time the hacker can hack your account and can get away your coins, i think you need to get a double protection to your wallet, or to put your coins in desktop wallet which can be consider as more safer as compare to online wallet.