It stores your data locally, is suprisingly easy to use and relies on battle tested GPG.
From the website: "The community has even produced a cross-platform GUI client, an Android app, an iOS app, a Firefox plugin, a Windows client, a pretty Python QML app, a nice Go GUI app, an interactive console UI, Alfred integration (1) (2) (3), a dmenu script, OS X integration, git credential integration, and even an emacs package."