As mentioned before, I do agree that this is by far the best AI there is for FAF.
Let me just try to follow up the other message that I sent above on M28AI playing the Seraphim. Because in the many games that I've meanwhile played, it seems that the Seraphim come with a bit of a challenge of their own for the AI, making it a much less challenging opponent. Energy management appears to be an issue, possibly in conjunction with the Quantum Rift Archways. After it has built a QRA (and it always builds multiple), it struggles with energy for quite some time and is keeping shields down etc. Also, it's typical for the AI to run into unit cap issues later, also complaining about it in the chat, while it keeps piling up all units in its base.
https://replay.faforever.com/22323052 is an example for this. It is having energy issues before, but after completing its 4th Quantum Rift Archway at 1:25, it takes until 2:09 (almost 45 minutes) to get it's energy handling back up and the shields stable.
Also, what the AI never tries as a Seraphim is building (their unique) nuke launchers for nuke spamming, or mass attacks with air units. Also experimental unit attacks as such are very rare, but that might just be because of the energy problems caused by the Quantum Rift Archways.
This is not intended as a complaint, but just as hopefully helpful feedback to improve this AI even further!