i ordered this after going through several sleep nests. i've used summer infant, aden & anais, and halo innovations. my baby's room gets pretty cold at night (we live in san francisco and sonoma county) and i typically have to keep a space heater in the rom to keep her warm. i don't like using blankets because she tends to twist herself in them and i don't feel it's safe overall. the aden & anais sleep sacks are super soft, but they wear out and snag easily. halo and summer infant sleep sacks are fine, but they don't keep my baby as warm as i'd like. she wakes up very cool to the touch and her hands are icicles.
with the deedee sleep sack, none of the aforementioned problems exist. she's warm, but not over-heated. the temperature in her room dips between 65-69 degrees and the deedee sleep sacks do great. for reference, i put her in cotton pajamas at night. during the colder nights, i'll put socks on her and if it's not too cold, i'll put her in a onesie with no socks.
the deedee sleep sack was pricey, but it's worth every penny. one thing i've noticed is that it seems to run small, but my baby is long for her age. she's 9 months old and about 22 pounds and i ordered the large. i originally got the medium, and though it fit, she would have outgrown it in about a month. the large is HUGE, but at least she can use it for a while. also, the large does not have the handy button tabs at the shoulders. other than a couple of small points, this is the perfect sleep sack. i will be purchasing this again for our next baby and will be giving them as gifts to my friends. great product!