You don't own a pixel?

I never used /e/ but I used iode (https://iode.tech/) and it worked really well. Main differences:

• Graphene doesn't support pattern unlock because they claim PIN is more secure. This is stupid because you can just as easily see what PIN someone typed as the pattern. Since PIN is less convenient most people will use finger print unlock which means you can be easily forced to unlock your phone against your will

• iode has support for shortcuts when using 3 button navigation, Graphene doesn't for some reason

• iode has really nice tracker blocker which can run next to a VPN, Graphene doesn't

• Graphene let's you install Google Services in a separate work profile and separate apps that have access to them from other apps. In iode you will have microG installed system wide

For me that were the biggest differences. When it comes to app support they worked pretty much the same. I'm on Graphene now and it would be too much work to change now but for my next phone I will most likely go with iode.

Fairphone can't meet graphene security standards.

Graphene isn't also that much better than the alternatives (when it comes to things other than security).

I don't believe Graphene supports Fairphone.

It’s mostly a thing of what’s available for your phone. For pixels 6 and newer (and I think some new motorolas as of recently) you can use graphene. If you are on fairphone or a bunch of other devices, you have support for e/OS. In general, graphene is a bit more secure than e/OS, so if you have the choice, it’s probably the way to go but if you don’t have a pixel and don’t want to buy one, e/OS is probably one of the better maintained degoogled android versions out there.
Here you can find a list with a feature comparison.

Because the hardware isn't from google.

My expetiences differ.

The default launcher regularly breaks, so I need to clean the cache, or wait until it succeeds. So for what I can, I use droidify or obtainium. Some apps also dont work properly as they are reliant on google services. Netflix comes to mind first.

Bank works, but governmental app (ID & payment) dont work, so I am still rel on work phone for those. Check forums, theres a list for these crucial apps and their status.

Other than that it's been mostly smooth experience.

I have the Fairphone 6 (not the plus) running /e/os. It's pleasant enough that when I had to use a vanilla android tablet I was kind of like (is this how you people live?! 😄 this is awful!)

I dont have this newest gen6 plus, just the slightly less new gen6 with e/os, but I wouldn't imagine the difference is huge. Has generally worked about as well as any regular android phone Ive had, with a few minor annoyances like the "paste" button for text often being invisible, such that I just have to press where it should be to make it work.