My daughter only ever fit in the heart to heart insert once, and then just seemed too big to fit comfortably. Then I didn't use it again until about 6months because she didn't seem to be able to get in a comfortable position, so I just used the hugabub which we both loved. I've now started using the ergo again since she turned 6 months and she seems really comfortable. It's really convenient because I can take the ergo and a single pram and have either my toddler in the pram and baby in the ergo on my front, or the baby in the pram and my toddler in the ergo on my back