Yes, I have used it several times. One example was in early April with a low of 39 F. I wasn't wearing any thermal type clothing and I was plenty warm but I am a somewhat warm sleeper. But as I do most of my backpacking in winter, fall, and spring I often do bring a UL down jacket and other thermal type clothing with me anyways. I could easily take it down to freezing but I wouldn't recommend that for most women since many tend to be colder sleepers.
I did notice that like with most double wide quilts and sleeping two people that there is the draft issue at times, especially if one or more of the people are restless sleepers.
I plan on sewing on some silk on the middle top to help with that for when it gets colder again.
BTW, both my wife and I also have separate single quilts to use when its below freezing. Hers is a 32 degree quilt and mine a 40 degree quilt. I find having the 2 single quilts with 1 double gives us a great flexibility and a lot choice with backpacking trips, especially since she is a much colder sleeper than I and that she doesn't always accompany me. There are times when she will bring one of the single quilts and I carry the double, which both of will use. We haven't tried it yet, but if it was significantly cold like 20 degrees and less, then we would bring all 3 quilts. (She rarely accompanies me when its that cold though.
Anyways, I think the quilt is pretty good for the price I paid for it--i had a 35% coupon for STP.