i heard some people have tried it to test out. it is not an approved client so i would wait for an official staff statement. @Shane can we get a UOF Orion pilot program in the works perhaps? not sure what the status of the client is atm.
I got a discord 'OK' from eppy a while back. At the moment, Orion is pretty much a client only for those willing to put up with a lot of inconvenience and learning curve for the sake of being an early adopter. It crashes fairly frequently and it can slow down to suboptimal levels in PVP and heavily populated areas.
On the plus side, this is about the only open-source UO client being actively developed, with active/involved devs who will address new bugs/issues as they arise. Conversely, Razor, UOSteam and Sallos are all closed-source and no longer being maintained, so if anything breaks them in the future, they will become unusable, and there's nothing we'd be able to do about it. The developers of Orion (Hotride and Aimed) are very cool and will chat with you about issues you're having.