Wonderful piece of gear IMO! At this point, I'm not sure what it would take to get me to go to a full length underquilt; the Yeti works too well. I've had the current 3-season down to 24F (maybe 25F, can't remember?) without any additional insulation below me. The kicker to that is that I wasn't even under a winter tarp at the time, so I had no real protection from the elements. I'm a little weird about cold admittadly, but the Yeti kicks!
The only thing I'm mad about is that Brandon waited till summer to debut the snap-in reflective liner. Now I gotta wait 2 whole seasons before I try that out. Yes, I'm pouting. What's your point?