I have a good ol' Baby Bjorn and a Bubba Moe. The Bubba Moe is very similar to the Nurture Sling. I am looking into a Hug-a-Bub or an Ergo though, they are meant to be better for baby's back than the Baby Bjorn.

The Ergo interests me as it can be used like a backpack. My DD (and all her cousins) were quite big with long legs, and none of us were able to use anything that had them on our fronts for more than 4 months or so, as they got too long to be able to walk with their legs hanging down your front.

The Bubba Moe sling was great to be able ot put DD on my back, and she loved it.