Hi Renee! First off, DO NOT buy a Baby Bjorn LOL! They are great when your bub is tiny, but the older they get, the more strain that is put on your shoulders.

I had a Baby Bjorn originally, but it was killing me because Kieran was such a big baby (still is). I did my research and ended up buying an Ergo baby carrier. It distributes babies weight onto your hips instead of your shoulders (just like a hiking backpack). In the Ergo you can wear bub on your front, hip or back. I can't wait for DH to wear him on his back. As you can tell I LOVE mine! A lot of BB girls have Ergos and most seem to love them!

Ergo have a website ergobaby.com where you can see how they work, I have some new ones on my website too. I became a stockist when I fell in love with mine LOL!

I've never used a sling so I can't comment on them sorry!