Bitcoin was well thought and designed when it was created and of course it is secure. It is more secure than anything else
I concur to this statement because bitcoin is not only safe but only if you keep using it in a manner that you are not inviting the troublers and hackers towards yourself.
It is said that keep yourself strong enough so that your enemy cannot think of attacking you, so in this field to keep ourselves strong there are already enough of the guidance, we just have to apply them on ourselves as standard operating procedures.