I've been using the IX UQ now for a few weeks now on my Warbonnet Blackbird hammock. This week I experimented with the layers a bit, wanted to test the single layer with torso heater out on its own. The night I went with a solo layer, the low happened to be 69*. It started out ok, but as the night progressed I had cold spots. Inside I had a summer UQ and a capilene baselayer long sleeve top and bottoms. I threw on an extra layer and was fine. From here on out I have used both layers and have had no cold spots. I am also a bit of a cold sleeper, so obviously one layer might work for those that are warmer sleepers.
I happened to recieve the UQ the weekend I spent with Dutch, and there was a bit of a cold snap. The low one particular night was 38* and I supplemented the UQ with a weathershield and was warm all night. So as much as the weather has allowed me to experiment the IX UQ has ranged from 38* to 69* using both layers, which is pretty cool IMO. It's light weight and has that wide of a temp range. I havent gotten it wet yet, so I can't say from experience if it retains heat when wet.
I also like the width of the quilt, it has great coverage IMO.
That's all I really have to report, it's definitely my new favorite piece of gear