We bought this baby carrier thinking it was the best available. Were we ever wrong! Just because big mainstream baby stores stock the baby bjorn doesn't mean it is any good.

Advantages are that it is easy to use. I sold mine on e-bay for a good amount so another advantage is that it has decent resale.

Disadvantages are many... To start, I found that once my son hit around 15lbs, the carrier really started to hurt my shoulders becasue that is where I was essentially carrying all his weight. Even though there is lumbar support in this model, the carrier doesn't spread any of your baby's weight to your hips. Also, it isn't very ergonomic for a baby. Babies prefer being in a froggy position at first and then more of a straddling position as they get older (knees slightly higher than their bottom). These positions are MUCH healthier for them than the hang-by-the-crotch bjorn position. There is lots of literature on this. Imagine hanging on your crotch like that - ouch!
Also, the baby bjorn isn't very versatile. It can't be worn on the back or hip.

I hate to bash a product that so many people clearly love, but I can't help but wonder whether they like it because they aren't aware of other options. In my opinon, a better choice would be a Beco or an Ergo carrier. Mei Tais and Wraps are also great two-shouldered carriers for people willing to give up buckles for something even more versatile.

Hope this helps!