Savior system is better for offline games.
uSQLite plugin was built to be expandable and safe for dedicated servers (where you own the server hardware) and online games, but can also be used on offline games as well.
When you build a C++ project in dedicated server mode, the uSQLite plugin is configured to generate DLLs, but when you package a build in Client mode then all its functions will not be generated to the Client, so online games have the security measure of making sure that all the save system is not present on any released Client binaries, while Server have a save system that works pretty close to what Savior plugin does.