There's really no way to tell if 1Password is safe. I use it and will continue to use it unless I hear otherwise. Pretty much any application you install on your machine that isn't open source could be considered unsafe since you can't view the code. That convenience application you have running 24/7 in your menubar could be logging all your keys for all you know. If 1Password had come out yesterday I'd be a bit more skeptical but it's been around for a while. Sure on any given release they could run "open backdoor!" and steal all your stuff... but so could a ton of other programs on your computer.