Liz, I had the R&B sling and both, baby and I didn't like it. I was too impatient and gave it away before my daughter was old enough for the hip position
One of my best buys was a baby wrap! It is super soft and supportive and can be worn in multiple ways, e.g. as a sling and as a front, back and side carrier. It can be used from newborn up to the age of 3. Only drawback is that it can be a bit of a mission to put it on, especially when you're on the go, and also to get baby out when he/ she is sleeping and you want to put him/ her down.
I also have a Kango pouch and used that a lot from about 5 months. Great for when you're out and about.