For most users we recommend CalyxOS as it has a good balance between security and usability with arguably more privacy out of the box. GrapheneOS is more secure out of the box but requires more initial setup and technical knowledge to be used as privately as CalyxOS. Calyx on the other hand can be used privately with little configuration out of the box. GrapheneOS also lacks a lot of the quality of life features offered by CalyxOS such as automatic app updates and integrations with Signal, F-Droid, and the Aurora store. While Play Store apps and even Play Services apps can run on GrapheneOS the process is much more intuitive and simplified on CalyxOS.