These blankets are great, I have purchased several of them.  They swaddle the way no ordinary blanket can because of the velcro flaps.  This way you don't have to worry about the baby coming out of the swaddle in the middle of the night and the risks involved with that.  They are also one of the few brands certified by the SIDS alliance.  I would highly recommend getting a couple of these blankets for any new parents with a young infant.  And the patterns like this Disney princess one are just too cute!

Definitely wash separately though since the Velcro will stick to other clothing items.