I use it for a small amount of stuff and it works really well. There is also an IPhone App that links directly to Dropbox.....However, I don't use it for anything sensitive so can't help you there. I believe it is safe and secure as can be, the only worry would be if Dropbox were to be forced to help any Government agencies....(Paranoid, Sorry.) I have been informed that you can use TrueCrypt within it, which would solve the security question. Not personally done that though....