I received a baba sling when my daughter was a newborn and I tried putting her in it but she wouldn't take to it and it wasn't very comfortable for me. Especially in the Summer the baba sling seemed too hot for my baby. I then purchased the Baby Bjorn Active Carrier which is meant to support the back and after a few outings, my baby got used to it and I have been using it ever since, so for my family, the carrier was a better choice. My back wasn't too good after the labour so the sling, which drapes over one side, would have caused more backache especially as baby gets heavier every week!
On the other hand my cousin said she prefers the sling. I guess it depends on which one your child is more comfortable in, and if you don't mind the use of it.
To teach is to learn twice