snakeplissken Hi there!
GrapheneOS doesn't include trackers in the OS to be able to accurately say how many people are using the OS, but there are some metrics that be used to get an estimate of current active GrapheneOS devices. The latest estimate is around 150k devices running GrapheneOS, as outlined here:
As for features, I do hope you'll give https://grapheneos.org/features a read.
If I have to give a list of 5 features, it would be the following:
- Defending against exploitation of unknown vulnerabilities - GrapheneOS goes to great lengths to harden the OS in order to lessen the impact of entire classes of vulnerabilities
- More Complete Patching - In addition to the above, GrapheneOS patches vulnerabilities than are not yet fixed in Android.
- Storage Scopes - Storage Scopes means that you can have granular control of what files/folders apps have access to, instead of granting them broad file permissions. In the future, there will be a similar feature for contacts, where you'll be able to grant an app access to specific contacts, instead of all of them.
- Vanadium: hardened WebView and default browser - A secure and hardened browser is extremely important, and it's even more important that apps that use the system WebView have a secure and hardened WebView to do that through, instead of one that may lag behind in updates or hardening.
- Sandboxed Google Play - All of the benefits mentioned above (there's plenty more in the features page, that's just a tiny subset of them) are on an OS that allows you to retain near-full app compatibility while ensuring that it's done in a secure way. Sandboxed Google Play makes it so you can optionally use Google Play Services as regular apps, which are confined by the same app sandboxed like all other apps instead of requiring privileged access like it normally does. The compatbility layer that GrapheneOS uses teaches it how to function using regular permissions instead of highly privileged ones, instead of crashing because it doesn't have them.
I hope this helps!