To answer my own question:
Conditions are AMAZING!
I rode everything once and most things 2 or more times. That includes the ambulance climb. sandy climb, and beginning section of the new loop which are all totally rideable without walking. Descents were sometimes a bit frightening for me due to the fast/slick/choppy hard packed snow, but totally doable. There is a tree that fell down in the bottom of the sandy bowl blocking the path although it looks like people are riding an alternate route that exits the bowl in a different place (off to the left) to avoid it.
Many sections of the southwest commuter path are waaay more icy/treacherous than the trails at QR, and personally I don't think I would be skilled enough to ride them safely without studs due to large sections of rutted glare ice.