I made quilts for the two youngest grandchildren (wasn't quilting yet for the oldest). They love them, and slept on their backs til they could turn themselves over. the youngest uses his all the time (he just turned 3) and it is flannel and chenille. Now that he is older he likes his ear covered when he turns onto his tummy. The middle one still has the flannel quilt on her bed,between her sheet and other blanket. It is really too small for her but she loves it.
As an aside, my younger child is 41. When he was born he loved to sleep on his back, and the dr. said "oh no, can't, he'll choke if he spits up". I'm glad SIDS rates are down though.