I have the heart to heart insert for DS 4 weeks 5kg and I really like it. With DD I didn't get Ergo till she was 5 months, so never needed it. One thing I like is that DS is so comfy in the insert that often when I get home can just put him down in the insert and he stays asleep, also if you need to put bub down anywhere for a minute (floor etc) don't need to worry about blanket as they are in insert.