Mark loves it. He sometimes gets frustrated when he can't move, but mainly he loves it and lifts his head reallly good. He's also rolled over already from his tummy to his side and back even. It scared him the first time he did it, but since then he's done it again and just babbled away. and like Katie, he likes to scoot around when he's on his tummy. So far, he's staying on his mat/quilt, but I'm sure that'll change fast.