I got on the waiting list for my IX underquilt back in May....got it sometime late June, after Mac upgraded me to the new Universal IX UQ.
Problem is, there just wasn't good weather to really try it out -- at that time of the year, the nighttime temperatures don't really drop below 80 at night...you more have to worry about cooling down than staying warm.
Having grown up in the Texas Hill Country, I tend to take the temperature ratings with a grain of salt....I generally stop wearing shorts when the temps start dropping below 70, so I'm a tough sell when it comes to me thinking of something as warm enough.
So this last weekend, with nighttime temps getting into the low 50s/upper 40s, that seemed a good time to test this thing out, while bringing along my HH Supershelter as backup (because I know that got me down to the low 40s with only slight discomfort, which was easily rectified by adjusting my sleeping bag).
We had made a minor adjustment, sewing loops to the sides like the HHSS had (my wife had gotten to test it a couple of weeks before when I couldn't get away, and she reported getting cold, because it kept shifting to one side or another out from under her).
Upon arrival at the campsite (after dark, as usual), I hung it as best I could. Unfortunately, I got cold, though I had guessed it was likely due to me not being able to see whether there were gaps at the time. So, the next morning, I tried hooking the ends up a little differently. I used a couple of mini-biners on the two ends of the tarp (whch was hanging separately from the hammock, and attached the shock cord at the head and foot of the UQ to these clips. This held it up tighter against the hammock, and the loops we had sewn on before allowed me to hold the sides in place. The only down side was that it would no linger shift to either side when using the bottom entry, so I had to be a little careful when entering the hammock.
When I got in Saturday night, the difference in warmth was much more apparent than before, and as the night went on, I found myself sweating, actually having to push off the sleeping bag from above me to cool down.
I'm sold! Lightweight and warm is definitely possible, even for me!
(oh, and another test, while I was at it, in case other people wonder about it) -- I tried rolling the hammock, IX UQ and Supershelter undercover up and putting it in the snakeskins. It *is* possible, but I had to really squeeze to get it all in there, so it seemed to defeat the purpose of the fast camp breakdown. I think I'll stick with using the snakeskins on the tarp, and just putting the hammock in a compression dry sack with my sleeping bag and pillow.