Ergo sounds like it may be what you are looking for. It holds quite a bit of weight (I think up to 70 pounds!) is very comfortable, and can go on the front and back. It can also be adapted for an infant if you have another baby.
That said, my favorite carrier is Moby Wrap which is the kind you tie. You may be able to find one at a natural parenting or diapering store to try on with your baby and see what you think. It is by far the most comfortable, adjusts for your baby, and is very adaptable. And of course the baby isn't in it until it is tied and wrapped so no worries about safety from that standpoint.
The slings that were recently recalled were the Infantino brand slings sold at places like Wal-Mart. Those were the type that went around one side of the body and had a big bag like pouch for the baby.
I have tried a whole lot of slings and my least favorite by far is the Baby Bjorn, very uncomfortable. I also have a MayaWrap which many people like but I was never a huge fan of. I also have several wrap slings that I liked okay but didn't love. The only type I have never tried is the kind where the baby sits on the hip, since that seems like it would be very uncomfortable to me. Also the Moby can be used in that way (you just adjust the way you tie) but I have never tried it. Good luck!