I am primarily a sling user and will still strongly recommend the sling to all mothers. However, to be realistic, when my babies reached the 10kg mark (thereabout), it does get a bit tedious to carry them in the sling due to the weight. Shoulders still ache even though I am very sure I use the sling correctly. The back is not spared too.
Recently, I bought an Ergo Babycarrier and it was such a godsend. It looks pretty much like the usual baby carrier, a la Baby Bjorn, but it is supposed to be ergonomically designed.
My rave about the Ergo is that it really delivers what it promises – being ergonomically design, it really takes the toil off carrying a heavy baby. What makes the difference? For the technicalities, please refer to their website for information. For me personally, it is the fact that the weight of the baby rests on your hip. That really takes the burden off the back and the shoulders. I used to own a Baby Bjorn and despite what was promised, I remember aching terribly just 30-60 minutes into carrying a 2-3 months old Dominic who was definitely less than 10 kg. I had to sit down and rest every so often.
Now, with the Ergo, I could go gallivanting with an 11kg Damien for hours and won’t feel any ache anywhere. Of course, I feel the weight and do feel tired. It would be unrealistic to expect featherlight weight. But there is a difference between being tired and being achy, which I am sure you will agree with me.
The other thing I really like about the Ergo is that I can piggyback Damien. With a Sarong Sling, I can also piggyback a child, but he would need to be older and able to hang on and not back flip. This is not possible with a younger child who may find it fun to carrying on witih antics like back flipping. With the Ergo, even young Damien can be securely piggybacked. This is really a godsend for me. Damien is a koala baby and often needs to be carried. I had to do things like cooking with one hand because the other hand would be needed to support him a little even though he was carried in a sarong sling. It is also kind of difficult to do things like cutting when he is carried on the side and thus obstructing the use of one arm. With the Ergo, he can be securely carried in the piggyback style, which is safer because he would be shielded away from the oil and heat during cooking. My two hands would be truly free to work. How I wish I found it earlier when Damien was younger and even more sticky!
Personally, I also find that piggybacking a child is less strenuous than carrying a child either at the side or the front. So I really like the fact that Ergo allows me this option. The latest Ergo model not only allows you to piggyback and front-carry, you can also do hip-carry with it!
The downside of the Ergo is that it is not very suitable for an infant. Technically, you can use it for an infant, but you will need to buy an infant insert separately. I have not tried it but judging by the picture, it does not seem as convenient and easy to use as a sarong sling. With the insert, it could also be potentially very hot for our climate.
The other disadvantage is nursing. For a toddler, you are advised to lower the shoulder straps such that the child is sitting lower, facing your breasts. I cannot master this. The only time I successfully tried this was when I sat down. Even then it was quite a strain. I cannot nurse on the move with the Ergo, unlike the sling. However, I know my friend can nurse her 2 year old in the Ergo this way. Perhaps I am not as flexible as she is! Whatever it is, I still think it is not quite convenient to nurse a child in the Ergo.
A minor disadvantage is the fact that when not in use, the Ergo is quite bulky to carry around, compared to a sling (the ones without thick paddings). The newer generation does not come with nice carrier bag too. Instead, you are given the option to buy the bag.
The first disadvantage does not bother me, since I use the sling when my babies are still small and only switch to Ergo when they are heavier. The second disadvantage poses a tad more inconvenience for me since my (at the time of this writing) 21 months old is still nursing. Nevertheless, I find ways to get around it, e.g. nursing him while in a car, or sitting somewhere, instead of trying to nurse him on the go while he is being carried in the Ergo.
All in all, I would say that the Ergo is indeed a very worthwhile investment for me.