While I can't say there is anything specifically wrong with the New Native Carrier Sling, it just wasn't the right one for me.  I think perhaps it was too big.  I didn't feel my newborn was safe when inside and found it uncomfortable when they were older and trying to use it as a hip sling.  I suggest you shop around and ask your friends to try out the slings they have to find the one that is right for you.

Bottom line, buy a sling.  I couldn't have survived without one.