I love our Baby Bjorn sling. Emma rarely falls asleep in her pram and several people on the school run have commented on how alert she is whenever they see her in it. This isn't a problem when she is fully awake as she will happily lie there and take it all in, but it can lead to a very fussy little girl if she is in her pram and is tired. The sling, on the other hand, acts rather like a tranquilizer. She is happily dozing within minutes of strapping her into it and generally remains so until you take her out again. This was extremely useful on our trip to the zoo on Sunday. Emma was quite content for the entire afternoon and it also freed up the pram to cart all the picnic food around!
On a side note, Lily was just the same in the pram, although she didn't always sleep in the sling either. I can't believe I have had two babies who don't sleep in prams when everyone says how unusual it is!