The UI mods I started to use from day one are: Better Civilization Icons, Better Espionage Screen, Better Trade Screen, More Lenses, Real Great People, Tomatekh's Historical Religions, Unique District Icons, Unit Report Screen. They all work without any noticeable glitches. I personally don't care at all for a production queue, so I have never bothered to install such mods and it is why I am not that interested if CQUI working. It is entirely a personal preference, so I understand if other people feel the game's UI is lacking without that mod.
Overall, mods seem to be working relatively fine. Some of the popular map packs do not work yet, as well as some custom-made natural wonders, but apart from that it is fine. Oh, and the More Barbarian XP mod also works just fine, for those of you who care for it (I do). The Gold Resource mod is also working just fine, as well as Diverse Beliefs and other religious enhancements. I personally don't see any problems with playing R&F and I am enjoying it immensely.