Sleep Problems: Infant, Simplicity

Baby Carriers or Slings?

Any advice on baby carriers for newborns and beyond six months? Feedback on pros/cons on brands like the ERGO, Baby Bjorn, Beco and Infantino backpack carrier would be great. I'd also love to hear feedback on reasons why someone would use a sling (I'm a bit afraid to use it given the recent recall) vs. carrier. Thanks!