[codethief]

I used CyanogenMod/LineageOS for the better part of a decade and switched to GrapheneOS a couple years ago and haven't looked back.

When it comes to security (and privacy), GrapheneOS blows LineageOS out of the water in pretty much every way, e.g.:

  - Arbitrary-length encryption passphrases
  - General security hardening: Memory hardening, sandbox hardening etc.
  - Non-rooted (i.e. much higher security barriers for malicious apps to take over control over your phone) 
  - No userdebug mode (LineageOS ROMs are often development builds which weaken the security of the OS, see e.g. https://github.com/GrapheneOS/os-issue-tracker/issues/284#issuecomment-690417436 )
  - Fully secured boot chain (in other words: A thief won't be able to do much with your phone)
  - Sandboxing of Google services (*if* you want to use them), i.e. Google no longer has admin access to your phone
  - Being able to restrict internet access for certain apps (that's a huge one in my book)
  - Being able to grant apps access only to select contacts from your contact list (contact scopes), and only select files/folders (storage scopes)

See https://grapheneos.org/features for a much longer list.

Now that I'm thinking about it, some of the above features have become so natural to me, that I find it wild that other AOSP-based ROMs (including Google's) don't have them. Moving away from GrapheneOS would be incredibly painful for me.

[josephcsible]

Not being able to have root on your own device is a downside of GrapheneOS, not a benefit.

[codethief]

Depends on where you stand. I could always build GrapheneOS myself and enable root again but I just don't have any need for it and prefer the stronger security guarantees disabling root comes with.

[e44858]

You absolutely can root GrapheneOS, just use the standard Magisk process. I think the only downside is that rooting disables secure boot.