I picked up one of these for DD around the time the weather got ridiculously frigid here in the midwest, and I must say that I love it. While the Halo fleece sleep sacks are great, and what we still use to this day for DS, I found it hard to have one on DD before putting her down to sleep as it "rode up" into her face when she was up on my shoulder burping or snuggling. It was also in the way if I snuck in one more diaper change before putting her down to sleep. Wrestling her arms into the arm holes when she was drowsy and ready for bed ticked her off and woke her up more than I wanted. The same was trtue with DS, but I didn't know there was an alternative.
The sleep nest is made of light cotton batting rather than fleece, and it has snaps at the shoulders, so I basically unzip, unsnap and butterfly the thing out in her crib before starting her bedtime routine, place her on top of it, and then quickly snap and zip as she acclimates to the crib and dozes off. It is nice and warm and even in her slightly chilly room in a cotton sleeper her hands are slightly warm to the touch during the night. It is more pricey than the Halo sacks, but I think we are getting enough use out of it (at least this winter!) to justify the cost.
Now if we could just get her to STTN consistently...well, I guess you can't have everything, right?
https://www.babydeedee.com/product_info/22/52
ETA: This is not an advertisement - LOL - I just re-read it and realized it sounds like one. I just wanted to share as I never thought to look for options other than the Halo sacks for cold weather.
BFP #1 5/2010 - Missed m/c at 8 weeks
BFP #2 2/2011
Baby G welcomed with love and relief 10/2011
Surprise BFP 1/8/2013...say what? Baby A arrived 9/2013
Motherhood is not for wimps