We were using regular swaddling blankets and Dr. Karp's "happiest baby" techniques for our son with much success. Then, however, he started getting stronger and able to squirm out of his swaddle (one arm, then two, legs, etc.) faster than we could get him in it. Even if he was in a really deep sleep he would eventually get his hands on his face and wake. We were getting really frustrated. We had the Kiddopotomus SwaddleMe, the Miracle Blanket - all worked to a degree (he grew out of the Miracle almost immediately - almost 10 lbs. at birth). I liked the SwaddleMe, but our squirmer could get out of those fairly quickly as well. The Woombie has solved our problems. Our baby can't get out of this one, and we are getting an extra hour or so of sleep overnight (5-6 hours as opposed to 4). Also, because they have more sizes, we were able to get a Woombie that fits our larger, still an infant (2 months this week and about 13 lbs.), baby that needs swaddling to be comfortable. The zipper works well and goes from the top down, which is helpful for diaper changing. It can be a little tricky to zip if you're half asleep or baby is especially squirmy. There is also a strip of fabric that protects the baby from having a zipper against their body (nice feature). If you'd like to see all their options (or, for more sizes) go to their website (just google it). We are very happy with this product (and we're getting some sleep, too).