Since his arrival, our son slept best swaddled. We first tried the zipadee-zip on a weekend in case it was a rough night, but he slept wonderfully! We have continued to use the sack since and have noticed no difference in his sleep than when he was swaddled.
We ordered 2 of the Snuggle Strap Bundles for our 2 month old twins. We transitioned from the Halo Sleep Sack. Both girls have transitioned with no problems and are sleeping even longer stretches at night! We love our Zipadee Zips!