Any advice about grobags or slepping bags? We're just at the stage of buying all this stuff for our baby due in 7 wks. I like the idea of a maintaining a constant temperature, not being able to kick the blankets off or get tiny fingers stuck in cellular blankets, or having to maintain the feet to foot position because there is nowhere to slip under. But someone has expressed concern about the possibility of babies slipping down inside of them. I think proper grow bags seem to have poppers under the arm to prevent this on newborns? Does anyone else have any experiences of using them which are either positive or negative and advice on where to buy the cheapest - they seem to be quite expensive! Thanks.