Not so much positive as negative but I contacted an ebay seller who was selling one of the Premaxx bag slings like this:
Hi
I am a big fan of babywearing and have carried all four of my children in a variety of slings over the years. I would encourage all parents to carry their children close to them as I know how convenient and easy it is.
That said, would you consider removing the text in your listing that says that this sling is suitable for newborns?
This kind of bag sling has been the subject of warnings in the US due to the risk of suffocation for tiny babies and one, called the Infantino Sling Rider has been recalled.
They are fine for bigger babes and the hip carry is great for a toddler but tiny weeny babies can end up in unsafe positions within the bag.
You can read more here here
http://babyslingsafety.blogspot.com/
With best wishes
Rachel
All I got in response was this: I just sell the product, thank you for contacting me.
Aaaargh! What can you do?