I primarily used a OnePlus 3 (non-3T) and a Nexus 4. The OnePlus 3 seemed to have a very active ROM community.

I tried many of the well-known ROMs: Lineage, Paranoid, Ressurection.

I also tried many of the OnePlus-specific ROMs, that were typically maintained by only one or two devs each.

Most of the features worked perfectly fine on both phones. But the deal-breakers were often the simple things: GPS (w/o downloading extra geolocation database services) and Bluetooth were the kickers for me. These services were consistently spotty across every ROM I tried.

My experience is as of a couple years ago. I have since moved away from the ROM scene, simply because I do not have the time to deal with this sort of stuff anymore.

A Pixel running stock AOSP with F-droid and Chromium is the bleeding edge of what's possible with open source. There's no better UI/UX in existence and the tragedy of it all is that outside of Android developers and software engineers most people never get to experience it at all.

The reality is that Librem is unnecessary because we have F-droid. There's nothing wrong with F-droid and as time goes on more mainstream apps will continue being brought over.

Too bad the Pixel doesn't have a headphone jack, otherwise I would have bought one. I've also heard it was pagued with hardware issues. Stuck on Nexus 5 + LineageOS for the time being.

GrapheneOS is sadly only available on Pixel devices.

Pixel 3a has a jack. Not supported yet by GrapheneOS, but it might be in the future. You can always self-compile your own plain AOSP.

I am stuck on nexus 5 + lineage. Sadly lineage is stuck on version 14 because of some Bluetooth bug.